diff --git a/TODO.md b/TODO.md
index f081fdf..bf07a08 100644
--- a/TODO.md
+++ b/TODO.md
@@ -5,7 +5,7 @@
 - json serialize with serde
 - sanity checks
 - tests
-- PyRef
+- PyRef https://pyo3.rs/v0.20.0/faq.html#pyo3get-clones-my-field
 - https://source.android.com/docs/core/runtime/dex-format#system-annotation
 
 
diff --git a/androscalpel/src/apk.rs b/androscalpel/src/apk.rs
index fa85244..f3327a9 100644
--- a/androscalpel/src/apk.rs
+++ b/androscalpel/src/apk.rs
@@ -7,6 +7,7 @@ use log::info;
 use pyo3::prelude::*;
 use pyo3::types::PyBytes;
 
+use crate::ins::CallSite;
 use crate::instructions;
 use crate::*;
 use androscalpel_serializer::Instruction as InsFormat;
diff --git a/androscalpel/src/code.rs b/androscalpel/src/code.rs
index 2a462d5..05cd306 100644
--- a/androscalpel/src/code.rs
+++ b/androscalpel/src/code.rs
@@ -4,7 +4,7 @@ use std::collections::HashSet;
 
 use pyo3::prelude::*;
 
-use crate::{DexString, IdField, IdMethod, IdMethodType, IdType, Instruction, MethodHandle};
+use crate::{ins::Instruction, DexString, IdField, IdMethod, IdMethodType, IdType, MethodHandle};
 
 // TODO: make this easy to edit/manipulate, maybe move to Method
 
diff --git a/androscalpel/src/dex_writer.rs b/androscalpel/src/dex_writer.rs
index bbacb73..97757af 100644
--- a/androscalpel/src/dex_writer.rs
+++ b/androscalpel/src/dex_writer.rs
@@ -13,8 +13,8 @@ use crate::Result;
 use crate::*;
 use androscalpel_serializer::*;
 
+use crate::ins::{CallSite, Instruction};
 use crate::instructions::*;
-use crate::Instruction;
 use androscalpel_serializer::Instruction as InsFormat;
 
 #[derive(Debug, Clone)]
@@ -112,7 +112,8 @@ impl Default for DexWriter {
         Self {
             header: HeaderItem {
                 magic: DexFileMagic {
-                    version: [0x30, 0x33, 0x39],
+                    //version: [0x30, 0x33, 0x39],
+                    version: [0x30, 0x33, 0x37],
                 }, // TODO: find a better default version
                 checksum: 0,
                 signature: [0u8; 20],
diff --git a/androscalpel/src/instructions.rs b/androscalpel/src/instructions.rs
index 0e5b249..5d57141 100644
--- a/androscalpel/src/instructions.rs
+++ b/androscalpel/src/instructions.rs
@@ -3463,9 +3463,13 @@ impl IntoPy<PyObject> for Instruction {
 #[pyclass]
 #[derive(Debug, Clone)]
 pub struct CallSite {
+    #[pyo3(get, set)]
     pub method_handle: MethodHandle,
+    #[pyo3(get, set)]
     pub name: DexString,
+    #[pyo3(get, set)]
     pub type_: IdMethodType,
+    #[pyo3(get, set)]
     pub args: Vec<DexValue>,
 }
 
@@ -3692,7 +3696,9 @@ impl Nop {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct Move {
+    #[pyo3(get, set)]
     pub from: u16,
+    #[pyo3(get, set)]
     pub to: u16,
 }
 
@@ -3809,7 +3815,9 @@ impl Move {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct MoveWide {
+    #[pyo3(get, set)]
     pub from: u16,
+    #[pyo3(get, set)]
     pub to: u16,
 }
 
@@ -3925,7 +3933,9 @@ impl MoveWide {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct MoveObject {
+    #[pyo3(get, set)]
     pub from: u16,
+    #[pyo3(get, set)]
     pub to: u16,
 }
 
@@ -4034,6 +4044,7 @@ impl MoveObject {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct MoveResult {
+    #[pyo3(get, set)]
     pub to: u8,
 }
 
@@ -4129,6 +4140,7 @@ impl MoveResult {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct MoveResultWide {
+    #[pyo3(get, set)]
     pub to: u8,
 }
 
@@ -4224,6 +4236,7 @@ impl MoveResultWide {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct MoveResultObject {
+    #[pyo3(get, set)]
     pub to: u8,
 }
 
@@ -4319,6 +4332,7 @@ impl MoveResultObject {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct MoveException {
+    #[pyo3(get, set)]
     pub to: u8,
 }
 
@@ -4510,6 +4524,7 @@ impl ReturnVoid {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct Return {
+    #[pyo3(get, set)]
     pub reg: u8,
 }
 
@@ -4605,6 +4620,7 @@ impl Return {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct ReturnWide {
+    #[pyo3(get, set)]
     pub reg: u8,
 }
 
@@ -4700,6 +4716,7 @@ impl ReturnWide {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct ReturnObject {
+    #[pyo3(get, set)]
     pub reg: u8,
 }
 
@@ -4803,7 +4820,9 @@ impl ReturnObject {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct Const {
+    #[pyo3(get, set)]
     pub reg: u8,
+    #[pyo3(get, set)]
     pub lit: i32,
 }
 
@@ -4925,7 +4944,9 @@ impl Const {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct ConstWide {
+    #[pyo3(get, set)]
     pub reg: u8,
+    #[pyo3(get, set)]
     pub lit: i64,
 }
 
@@ -5045,7 +5066,9 @@ impl ConstWide {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct ConstString {
+    #[pyo3(get, set)]
     pub reg: u8,
+    #[pyo3(get, set)]
     pub lit: DexString,
 }
 
@@ -5144,7 +5167,9 @@ impl ConstString {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct ConstClass {
+    #[pyo3(get, set)]
     pub reg: u8,
+    #[pyo3(get, set)]
     pub lit: IdType,
 }
 
@@ -5247,6 +5272,7 @@ impl ConstClass {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct MonitorEnter {
+    #[pyo3(get, set)]
     pub reg: u8,
 }
 
@@ -5342,6 +5368,7 @@ impl MonitorEnter {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct MonitorExit {
+    #[pyo3(get, set)]
     pub reg: u8,
 }
 
@@ -5438,7 +5465,9 @@ impl MonitorExit {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct CheckCast {
+    #[pyo3(get, set)]
     pub reg: u8,
+    #[pyo3(get, set)]
     pub lit: IdType,
 }
 
@@ -5542,8 +5571,11 @@ impl CheckCast {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct InstanceOf {
+    #[pyo3(get, set)]
     pub dest: u8,
+    #[pyo3(get, set)]
     pub obj: u8,
+    #[pyo3(get, set)]
     pub lit: IdType,
 }
 
@@ -5672,7 +5704,9 @@ impl InstanceOf {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct ArrayLength {
+    #[pyo3(get, set)]
     pub dest: u8,
+    #[pyo3(get, set)]
     pub arr: u8,
 }
 
@@ -5787,7 +5821,9 @@ impl ArrayLength {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct NewInstance {
+    #[pyo3(get, set)]
     pub reg: u8,
+    #[pyo3(get, set)]
     pub lit: IdType,
 }
 
@@ -5890,8 +5926,11 @@ impl NewInstance {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct NewArray {
+    #[pyo3(get, set)]
     pub reg: u8,
+    #[pyo3(get, set)]
     pub size_reg: u8,
+    #[pyo3(get, set)]
     pub lit: IdType,
 }
 
@@ -6028,7 +6067,9 @@ impl NewArray {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct FilledNewArray {
+    #[pyo3(get, set)]
     pub type_: IdType,
+    #[pyo3(get, set)]
     pub reg_values: Vec<u16>,
 }
 
@@ -6238,8 +6279,11 @@ impl FilledNewArray {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct FillArrayData {
+    #[pyo3(get, set)]
     pub arr: u8,
+    #[pyo3(get, set)]
     pub elt_width: u16,
+    #[pyo3(get, set)]
     pub data: Vec<u8>,
 }
 
@@ -6393,6 +6437,7 @@ impl FillArrayData {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct Throw {
+    #[pyo3(get, set)]
     pub reg: u8,
 }
 
@@ -6488,6 +6533,7 @@ impl Throw {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct Goto {
+    #[pyo3(get, set)]
     pub label: String,
 }
 
@@ -6627,7 +6673,9 @@ impl Goto {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct Switch {
+    #[pyo3(get, set)]
     pub reg: u8,
+    #[pyo3(get, set)]
     pub branches: HashMap<i32, String>,
 }
 
@@ -6752,8 +6800,11 @@ impl Switch {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct CmpLFloat {
+    #[pyo3(get, set)]
     pub dest: u8,
+    #[pyo3(get, set)]
     pub b: u8,
+    #[pyo3(get, set)]
     pub c: u8,
 }
 
@@ -6859,8 +6910,11 @@ impl CmpLFloat {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct CmpGFloat {
+    #[pyo3(get, set)]
     pub dest: u8,
+    #[pyo3(get, set)]
     pub b: u8,
+    #[pyo3(get, set)]
     pub c: u8,
 }
 
@@ -6966,8 +7020,11 @@ impl CmpGFloat {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct CmpLDouble {
+    #[pyo3(get, set)]
     pub dest: u8,
+    #[pyo3(get, set)]
     pub b: u8,
+    #[pyo3(get, set)]
     pub c: u8,
 }
 
@@ -7073,8 +7130,11 @@ impl CmpLDouble {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct CmpGDouble {
+    #[pyo3(get, set)]
     pub dest: u8,
+    #[pyo3(get, set)]
     pub b: u8,
+    #[pyo3(get, set)]
     pub c: u8,
 }
 
@@ -7179,8 +7239,11 @@ impl CmpGDouble {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct CmpLong {
+    #[pyo3(get, set)]
     pub dest: u8,
+    #[pyo3(get, set)]
     pub b: u8,
+    #[pyo3(get, set)]
     pub c: u8,
 }
 
@@ -7281,8 +7344,11 @@ impl CmpLong {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct IfEq {
+    #[pyo3(get, set)]
     pub a: u8,
+    #[pyo3(get, set)]
     pub b: u8,
+    #[pyo3(get, set)]
     pub label: String,
 }
 
@@ -7400,8 +7466,11 @@ impl IfEq {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct IfNe {
+    #[pyo3(get, set)]
     pub a: u8,
+    #[pyo3(get, set)]
     pub b: u8,
+    #[pyo3(get, set)]
     pub label: String,
 }
 
@@ -7520,8 +7589,11 @@ impl IfNe {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct IfLt {
+    #[pyo3(get, set)]
     pub a: u8,
+    #[pyo3(get, set)]
     pub b: u8,
+    #[pyo3(get, set)]
     pub label: String,
 }
 
@@ -7640,8 +7712,11 @@ impl IfLt {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct IfGe {
+    #[pyo3(get, set)]
     pub a: u8,
+    #[pyo3(get, set)]
     pub b: u8,
+    #[pyo3(get, set)]
     pub label: String,
 }
 
@@ -7760,8 +7835,11 @@ impl IfGe {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct IfGt {
+    #[pyo3(get, set)]
     pub a: u8,
+    #[pyo3(get, set)]
     pub b: u8,
+    #[pyo3(get, set)]
     pub label: String,
 }
 
@@ -7880,8 +7958,11 @@ impl IfGt {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct IfLe {
+    #[pyo3(get, set)]
     pub a: u8,
+    #[pyo3(get, set)]
     pub b: u8,
+    #[pyo3(get, set)]
     pub label: String,
 }
 
@@ -8000,7 +8081,9 @@ impl IfLe {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct IfEqZ {
+    #[pyo3(get, set)]
     pub a: u8,
+    #[pyo3(get, set)]
     pub label: String,
 }
 
@@ -8101,7 +8184,9 @@ impl IfEqZ {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct IfNeZ {
+    #[pyo3(get, set)]
     pub a: u8,
+    #[pyo3(get, set)]
     pub label: String,
 }
 
@@ -8202,7 +8287,9 @@ impl IfNeZ {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct IfLtZ {
+    #[pyo3(get, set)]
     pub a: u8,
+    #[pyo3(get, set)]
     pub label: String,
 }
 
@@ -8303,7 +8390,9 @@ impl IfLtZ {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct IfGeZ {
+    #[pyo3(get, set)]
     pub a: u8,
+    #[pyo3(get, set)]
     pub label: String,
 }
 
@@ -8404,7 +8493,9 @@ impl IfGeZ {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct IfGtZ {
+    #[pyo3(get, set)]
     pub a: u8,
+    #[pyo3(get, set)]
     pub label: String,
 }
 
@@ -8505,7 +8596,9 @@ impl IfGtZ {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct IfLeZ {
+    #[pyo3(get, set)]
     pub a: u8,
+    #[pyo3(get, set)]
     pub label: String,
 }
 
@@ -8606,8 +8699,11 @@ impl IfLeZ {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct AGet {
+    #[pyo3(get, set)]
     pub dest: u8,
+    #[pyo3(get, set)]
     pub arr: u8,
+    #[pyo3(get, set)]
     pub idx: u8,
 }
 
@@ -8708,8 +8804,11 @@ impl AGet {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct AGetWide {
+    #[pyo3(get, set)]
     pub dest: u8,
+    #[pyo3(get, set)]
     pub arr: u8,
+    #[pyo3(get, set)]
     pub idx: u8,
 }
 
@@ -8810,8 +8909,11 @@ impl AGetWide {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct AGetObject {
+    #[pyo3(get, set)]
     pub dest: u8,
+    #[pyo3(get, set)]
     pub arr: u8,
+    #[pyo3(get, set)]
     pub idx: u8,
 }
 
@@ -8912,8 +9014,11 @@ impl AGetObject {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct AGetBoolean {
+    #[pyo3(get, set)]
     pub dest: u8,
+    #[pyo3(get, set)]
     pub arr: u8,
+    #[pyo3(get, set)]
     pub idx: u8,
 }
 
@@ -9014,8 +9119,11 @@ impl AGetBoolean {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct AGetByte {
+    #[pyo3(get, set)]
     pub dest: u8,
+    #[pyo3(get, set)]
     pub arr: u8,
+    #[pyo3(get, set)]
     pub idx: u8,
 }
 
@@ -9116,8 +9224,11 @@ impl AGetByte {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct AGetChar {
+    #[pyo3(get, set)]
     pub dest: u8,
+    #[pyo3(get, set)]
     pub arr: u8,
+    #[pyo3(get, set)]
     pub idx: u8,
 }
 
@@ -9218,8 +9329,11 @@ impl AGetChar {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct AGetShort {
+    #[pyo3(get, set)]
     pub dest: u8,
+    #[pyo3(get, set)]
     pub arr: u8,
+    #[pyo3(get, set)]
     pub idx: u8,
 }
 
@@ -9320,8 +9434,11 @@ impl AGetShort {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct APut {
+    #[pyo3(get, set)]
     pub from: u8,
+    #[pyo3(get, set)]
     pub arr: u8,
+    #[pyo3(get, set)]
     pub idx: u8,
 }
 
@@ -9422,8 +9539,11 @@ impl APut {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct APutWide {
+    #[pyo3(get, set)]
     pub from: u8,
+    #[pyo3(get, set)]
     pub arr: u8,
+    #[pyo3(get, set)]
     pub idx: u8,
 }
 
@@ -9524,8 +9644,11 @@ impl APutWide {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct APutObject {
+    #[pyo3(get, set)]
     pub from: u8,
+    #[pyo3(get, set)]
     pub arr: u8,
+    #[pyo3(get, set)]
     pub idx: u8,
 }
 
@@ -9626,8 +9749,11 @@ impl APutObject {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct APutBoolean {
+    #[pyo3(get, set)]
     pub from: u8,
+    #[pyo3(get, set)]
     pub arr: u8,
+    #[pyo3(get, set)]
     pub idx: u8,
 }
 
@@ -9728,8 +9854,11 @@ impl APutBoolean {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct APutByte {
+    #[pyo3(get, set)]
     pub from: u8,
+    #[pyo3(get, set)]
     pub arr: u8,
+    #[pyo3(get, set)]
     pub idx: u8,
 }
 
@@ -9830,8 +9959,11 @@ impl APutByte {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct APutChar {
+    #[pyo3(get, set)]
     pub from: u8,
+    #[pyo3(get, set)]
     pub arr: u8,
+    #[pyo3(get, set)]
     pub idx: u8,
 }
 
@@ -9932,8 +10064,11 @@ impl APutChar {
 #[pyclass]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct APutShort {
+    #[pyo3(get, set)]
     pub from: u8,
+    #[pyo3(get, set)]
     pub arr: u8,
+    #[pyo3(get, set)]
     pub idx: u8,
 }
 
@@ -10036,8 +10171,11 @@ impl APutShort {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct IGet {
+    #[pyo3(get, set)]
     pub to: u8,
+    #[pyo3(get, set)]
     pub obj: u8,
+    #[pyo3(get, set)]
     pub field: IdField,
 }
 
@@ -10165,8 +10303,11 @@ impl IGet {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct IGetWide {
+    #[pyo3(get, set)]
     pub to: u8,
+    #[pyo3(get, set)]
     pub obj: u8,
+    #[pyo3(get, set)]
     pub field: IdField,
 }
 
@@ -10298,8 +10439,11 @@ impl IGetWide {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct IGetObject {
+    #[pyo3(get, set)]
     pub to: u8,
+    #[pyo3(get, set)]
     pub obj: u8,
+    #[pyo3(get, set)]
     pub field: IdField,
 }
 
@@ -10431,8 +10575,11 @@ impl IGetObject {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct IGetBoolean {
+    #[pyo3(get, set)]
     pub to: u8,
+    #[pyo3(get, set)]
     pub obj: u8,
+    #[pyo3(get, set)]
     pub field: IdField,
 }
 
@@ -10565,8 +10712,11 @@ impl IGetBoolean {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct IGetByte {
+    #[pyo3(get, set)]
     pub to: u8,
+    #[pyo3(get, set)]
     pub obj: u8,
+    #[pyo3(get, set)]
     pub field: IdField,
 }
 
@@ -10698,8 +10848,11 @@ impl IGetByte {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct IGetChar {
+    #[pyo3(get, set)]
     pub to: u8,
+    #[pyo3(get, set)]
     pub obj: u8,
+    #[pyo3(get, set)]
     pub field: IdField,
 }
 
@@ -10831,8 +10984,11 @@ impl IGetChar {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct IGetShort {
+    #[pyo3(get, set)]
     pub to: u8,
+    #[pyo3(get, set)]
     pub obj: u8,
+    #[pyo3(get, set)]
     pub field: IdField,
 }
 
@@ -10964,8 +11120,11 @@ impl IGetShort {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct IPut {
+    #[pyo3(get, set)]
     pub from: u8,
+    #[pyo3(get, set)]
     pub obj: u8,
+    #[pyo3(get, set)]
     pub field: IdField,
 }
 
@@ -11093,8 +11252,11 @@ impl IPut {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct IPutWide {
+    #[pyo3(get, set)]
     pub from: u8,
+    #[pyo3(get, set)]
     pub obj: u8,
+    #[pyo3(get, set)]
     pub field: IdField,
 }
 
@@ -11226,8 +11388,11 @@ impl IPutWide {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct IPutObject {
+    #[pyo3(get, set)]
     pub from: u8,
+    #[pyo3(get, set)]
     pub obj: u8,
+    #[pyo3(get, set)]
     pub field: IdField,
 }
 
@@ -11359,8 +11524,11 @@ impl IPutObject {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct IPutBoolean {
+    #[pyo3(get, set)]
     pub from: u8,
+    #[pyo3(get, set)]
     pub obj: u8,
+    #[pyo3(get, set)]
     pub field: IdField,
 }
 
@@ -11492,8 +11660,11 @@ impl IPutBoolean {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct IPutByte {
+    #[pyo3(get, set)]
     pub from: u8,
+    #[pyo3(get, set)]
     pub obj: u8,
+    #[pyo3(get, set)]
     pub field: IdField,
 }
 
@@ -11625,8 +11796,11 @@ impl IPutByte {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct IPutChar {
+    #[pyo3(get, set)]
     pub from: u8,
+    #[pyo3(get, set)]
     pub obj: u8,
+    #[pyo3(get, set)]
     pub field: IdField,
 }
 
@@ -11758,8 +11932,11 @@ impl IPutChar {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct IPutShort {
+    #[pyo3(get, set)]
     pub from: u8,
+    #[pyo3(get, set)]
     pub obj: u8,
+    #[pyo3(get, set)]
     pub field: IdField,
 }
 
@@ -11889,7 +12066,9 @@ impl IPutShort {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct SGet {
+    #[pyo3(get, set)]
     pub to: u8,
+    #[pyo3(get, set)]
     pub field: IdField,
 }
 
@@ -11990,7 +12169,9 @@ impl SGet {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct SGetWide {
+    #[pyo3(get, set)]
     pub to: u8,
+    #[pyo3(get, set)]
     pub field: IdField,
 }
 
@@ -12095,7 +12276,9 @@ impl SGetWide {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct SGetObject {
+    #[pyo3(get, set)]
     pub to: u8,
+    #[pyo3(get, set)]
     pub field: IdField,
 }
 
@@ -12200,7 +12383,9 @@ impl SGetObject {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct SGetBoolean {
+    #[pyo3(get, set)]
     pub to: u8,
+    #[pyo3(get, set)]
     pub field: IdField,
 }
 
@@ -12305,7 +12490,9 @@ impl SGetBoolean {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct SGetByte {
+    #[pyo3(get, set)]
     pub to: u8,
+    #[pyo3(get, set)]
     pub field: IdField,
 }
 
@@ -12410,7 +12597,9 @@ impl SGetByte {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct SGetChar {
+    #[pyo3(get, set)]
     pub to: u8,
+    #[pyo3(get, set)]
     pub field: IdField,
 }
 
@@ -12515,7 +12704,9 @@ impl SGetChar {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct SGetShort {
+    #[pyo3(get, set)]
     pub to: u8,
+    #[pyo3(get, set)]
     pub field: IdField,
 }
 
@@ -12620,7 +12811,9 @@ impl SGetShort {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct SPut {
+    #[pyo3(get, set)]
     pub from: u8,
+    #[pyo3(get, set)]
     pub field: IdField,
 }
 
@@ -12726,7 +12919,9 @@ impl SPut {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct SPutWide {
+    #[pyo3(get, set)]
     pub from: u8,
+    #[pyo3(get, set)]
     pub field: IdField,
 }
 
@@ -12831,7 +13026,9 @@ impl SPutWide {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct SPutObject {
+    #[pyo3(get, set)]
     pub from: u8,
+    #[pyo3(get, set)]
     pub field: IdField,
 }
 
@@ -12936,7 +13133,9 @@ impl SPutObject {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct SPutBoolean {
+    #[pyo3(get, set)]
     pub from: u8,
+    #[pyo3(get, set)]
     pub field: IdField,
 }
 
@@ -13041,7 +13240,9 @@ impl SPutBoolean {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct SPutByte {
+    #[pyo3(get, set)]
     pub from: u8,
+    #[pyo3(get, set)]
     pub field: IdField,
 }
 
@@ -13146,7 +13347,9 @@ impl SPutByte {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct SPutChar {
+    #[pyo3(get, set)]
     pub from: u8,
+    #[pyo3(get, set)]
     pub field: IdField,
 }
 
@@ -13251,7 +13454,9 @@ impl SPutChar {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct SPutShort {
+    #[pyo3(get, set)]
     pub from: u8,
+    #[pyo3(get, set)]
     pub field: IdField,
 }
 
@@ -13356,7 +13561,9 @@ impl SPutShort {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct InvokeVirtual {
+    #[pyo3(get, set)]
     pub method: IdMethod,
+    #[pyo3(get, set)]
     pub args: Vec<u16>,
 }
 
@@ -13561,7 +13768,9 @@ impl InvokeVirtual {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct InvokeSuper {
+    #[pyo3(get, set)]
     pub method: IdMethod,
+    #[pyo3(get, set)]
     pub args: Vec<u16>,
 }
 
@@ -13766,7 +13975,9 @@ impl InvokeSuper {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct InvokeDirect {
+    #[pyo3(get, set)]
     pub method: IdMethod,
+    #[pyo3(get, set)]
     pub args: Vec<u16>,
 }
 
@@ -13971,7 +14182,9 @@ impl InvokeDirect {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct InvokeStatic {
+    #[pyo3(get, set)]
     pub method: IdMethod,
+    #[pyo3(get, set)]
     pub args: Vec<u16>,
 }
 
@@ -14176,7 +14389,9 @@ impl InvokeStatic {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct InvokeInterface {
+    #[pyo3(get, set)]
     pub method: IdMethod,
+    #[pyo3(get, set)]
     pub args: Vec<u16>,
 }
 
@@ -25507,8 +25722,11 @@ impl UshrIntLit {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct InvokePolymorphic {
+    #[pyo3(get, set)]
     pub method: IdMethod,
+    #[pyo3(get, set)]
     pub proto: IdMethodType,
+    #[pyo3(get, set)]
     pub args: Vec<u16>,
 }
 
@@ -25732,7 +25950,9 @@ impl InvokePolymorphic {
 #[pyclass]
 #[derive(Debug, Clone)]
 pub struct InvokeCustom {
+    #[pyo3(get, set)]
     pub call_site: CallSite,
+    #[pyo3(get, set)]
     pub args: Vec<u16>,
 }
 
@@ -25935,7 +26155,9 @@ impl InvokeCustom {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct ConstMethodHandle {
+    #[pyo3(get, set)]
     pub handle: MethodHandle,
+    #[pyo3(get, set)]
     pub to: u8,
 }
 
@@ -26038,7 +26260,9 @@ impl ConstMethodHandle {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct ConstMethodType {
+    #[pyo3(get, set)]
     pub proto: IdMethodType,
+    #[pyo3(get, set)]
     pub to: u8,
 }
 
@@ -26143,6 +26367,7 @@ impl ConstMethodType {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct Try {
+    #[pyo3(get, set)]
     pub end_label: String,
     /// The  list of exceptions and their associated handler label.
     ///
@@ -26150,7 +26375,9 @@ pub struct Try {
     ///
     /// The handler are sorted: if severat Exception Type match an exceptions, the
     /// the handler used is the first in the list.
+    #[pyo3(get, set)]
     pub handlers: Vec<(IdType, String)>,
+    #[pyo3(get, set)]
     pub default_handler: Option<String>,
 }
 
@@ -26277,6 +26504,7 @@ impl Try {
 #[pyclass]
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct Label {
+    #[pyo3(get, set)]
     pub name: String,
 }
 
diff --git a/androscalpel/src/lib.rs b/androscalpel/src/lib.rs
index a67b995..7375fe9 100644
--- a/androscalpel/src/lib.rs
+++ b/androscalpel/src/lib.rs
@@ -24,7 +24,7 @@ pub use dex_id::*;
 pub use dex_string::*;
 pub use dex_writer::*;
 pub use field::*;
-pub use instructions::{CallSite, Instruction};
+pub use instructions as ins;
 pub use method::*;
 pub use method_handle::*;
 pub use scalar::*;
@@ -32,7 +32,7 @@ pub use value::*;
 
 /// Androscalpel.
 #[pymodule]
-fn androscalpel(_py: Python, m: &PyModule) -> PyResult<()> {
+fn androscalpel(py: Python, m: &PyModule) -> PyResult<()> {
     pyo3_log::init();
     m.add_class::<DexNull>()?;
     m.add_class::<DexBoolean>()?;
@@ -71,5 +71,210 @@ fn androscalpel(_py: Python, m: &PyModule) -> PyResult<()> {
     m.add_class::<Class>()?;
     m.add_class::<Code>()?;
     m.add_class::<Apk>()?;
+
+    let ins_module = PyModule::new(py, "ins")?;
+    androscalpel_ins(py, ins_module)?;
+    m.add_submodule(ins_module)?;
+
+    Ok(())
+}
+
+/// Dalvik opcode for Androscalpel.
+fn androscalpel_ins(_py: Python, m: &PyModule) -> PyResult<()> {
+    m.add_class::<ins::CallSite>()?;
+    m.add_class::<ins::Nop>()?;
+    m.add_class::<ins::Move>()?;
+    m.add_class::<ins::MoveWide>()?;
+    m.add_class::<ins::MoveObject>()?;
+    m.add_class::<ins::MoveResult>()?;
+    m.add_class::<ins::MoveResultWide>()?;
+    m.add_class::<ins::MoveResultObject>()?;
+    m.add_class::<ins::MoveException>()?;
+    m.add_class::<ins::ReturnVoid>()?;
+    m.add_class::<ins::Return>()?;
+    m.add_class::<ins::ReturnWide>()?;
+    m.add_class::<ins::ReturnObject>()?;
+    m.add_class::<ins::Const>()?;
+    m.add_class::<ins::ConstWide>()?;
+    m.add_class::<ins::ConstString>()?;
+    m.add_class::<ins::ConstClass>()?;
+    m.add_class::<ins::MonitorEnter>()?;
+    m.add_class::<ins::MonitorExit>()?;
+    m.add_class::<ins::CheckCast>()?;
+    m.add_class::<ins::InstanceOf>()?;
+    m.add_class::<ins::ArrayLength>()?;
+    m.add_class::<ins::NewInstance>()?;
+    m.add_class::<ins::NewArray>()?;
+    m.add_class::<ins::FilledNewArray>()?;
+    m.add_class::<ins::FillArrayData>()?;
+    m.add_class::<ins::Throw>()?;
+    m.add_class::<ins::Goto>()?;
+    m.add_class::<ins::Switch>()?;
+    m.add_class::<ins::CmpLFloat>()?;
+    m.add_class::<ins::CmpGFloat>()?;
+    m.add_class::<ins::CmpLDouble>()?;
+    m.add_class::<ins::CmpGDouble>()?;
+    m.add_class::<ins::CmpLong>()?;
+    m.add_class::<ins::IfEq>()?;
+    m.add_class::<ins::IfNe>()?;
+    m.add_class::<ins::IfLt>()?;
+    m.add_class::<ins::IfGe>()?;
+    m.add_class::<ins::IfGt>()?;
+    m.add_class::<ins::IfLe>()?;
+    m.add_class::<ins::IfEqZ>()?;
+    m.add_class::<ins::IfNeZ>()?;
+    m.add_class::<ins::IfLtZ>()?;
+    m.add_class::<ins::IfGeZ>()?;
+    m.add_class::<ins::IfGtZ>()?;
+    m.add_class::<ins::IfLeZ>()?;
+    m.add_class::<ins::AGet>()?;
+    m.add_class::<ins::AGetWide>()?;
+    m.add_class::<ins::AGetObject>()?;
+    m.add_class::<ins::AGetBoolean>()?;
+    m.add_class::<ins::AGetByte>()?;
+    m.add_class::<ins::AGetChar>()?;
+    m.add_class::<ins::AGetShort>()?;
+    m.add_class::<ins::APut>()?;
+    m.add_class::<ins::APutWide>()?;
+    m.add_class::<ins::APutObject>()?;
+    m.add_class::<ins::APutBoolean>()?;
+    m.add_class::<ins::APutByte>()?;
+    m.add_class::<ins::APutChar>()?;
+    m.add_class::<ins::APutShort>()?;
+    m.add_class::<ins::IGet>()?;
+    m.add_class::<ins::IGetWide>()?;
+    m.add_class::<ins::IGetObject>()?;
+    m.add_class::<ins::IGetBoolean>()?;
+    m.add_class::<ins::IGetByte>()?;
+    m.add_class::<ins::IGetChar>()?;
+    m.add_class::<ins::IGetShort>()?;
+    m.add_class::<ins::IPut>()?;
+    m.add_class::<ins::IPutWide>()?;
+    m.add_class::<ins::IPutObject>()?;
+    m.add_class::<ins::IPutBoolean>()?;
+    m.add_class::<ins::IPutByte>()?;
+    m.add_class::<ins::IPutChar>()?;
+    m.add_class::<ins::IPutShort>()?;
+    m.add_class::<ins::SGet>()?;
+    m.add_class::<ins::SGetWide>()?;
+    m.add_class::<ins::SGetObject>()?;
+    m.add_class::<ins::SGetBoolean>()?;
+    m.add_class::<ins::SGetByte>()?;
+    m.add_class::<ins::SGetChar>()?;
+    m.add_class::<ins::SGetShort>()?;
+    m.add_class::<ins::SPut>()?;
+    m.add_class::<ins::SPutWide>()?;
+    m.add_class::<ins::SPutObject>()?;
+    m.add_class::<ins::SPutBoolean>()?;
+    m.add_class::<ins::SPutByte>()?;
+    m.add_class::<ins::SPutChar>()?;
+    m.add_class::<ins::SPutShort>()?;
+    m.add_class::<ins::InvokeVirtual>()?;
+    m.add_class::<ins::InvokeSuper>()?;
+    m.add_class::<ins::InvokeDirect>()?;
+    m.add_class::<ins::InvokeStatic>()?;
+    m.add_class::<ins::InvokeInterface>()?;
+    m.add_class::<ins::NegInt>()?;
+    m.add_class::<ins::NotInt>()?;
+    m.add_class::<ins::NegLong>()?;
+    m.add_class::<ins::NotLong>()?;
+    m.add_class::<ins::NegFloat>()?;
+    m.add_class::<ins::NegDouble>()?;
+    m.add_class::<ins::IntToLong>()?;
+    m.add_class::<ins::IntToFloat>()?;
+    m.add_class::<ins::IntToDouble>()?;
+    m.add_class::<ins::LongToInt>()?;
+    m.add_class::<ins::LongToFloat>()?;
+    m.add_class::<ins::LongToDouble>()?;
+    m.add_class::<ins::FloatToInt>()?;
+    m.add_class::<ins::FloatToLong>()?;
+    m.add_class::<ins::FloatToDouble>()?;
+    m.add_class::<ins::DoubleToInt>()?;
+    m.add_class::<ins::DoubleToLong>()?;
+    m.add_class::<ins::DoubleToFloat>()?;
+    m.add_class::<ins::IntToByte>()?;
+    m.add_class::<ins::IntToChar>()?;
+    m.add_class::<ins::IntToShort>()?;
+    m.add_class::<ins::AddInt>()?;
+    m.add_class::<ins::SubInt>()?;
+    m.add_class::<ins::MulInt>()?;
+    m.add_class::<ins::DivInt>()?;
+    m.add_class::<ins::RemInt>()?;
+    m.add_class::<ins::AndInt>()?;
+    m.add_class::<ins::OrInt>()?;
+    m.add_class::<ins::XorInt>()?;
+    m.add_class::<ins::ShlInt>()?;
+    m.add_class::<ins::ShrInt>()?;
+    m.add_class::<ins::UshrInt>()?;
+    m.add_class::<ins::AddLong>()?;
+    m.add_class::<ins::SubLong>()?;
+    m.add_class::<ins::MulLong>()?;
+    m.add_class::<ins::DivLong>()?;
+    m.add_class::<ins::RemLong>()?;
+    m.add_class::<ins::AndLong>()?;
+    m.add_class::<ins::OrLong>()?;
+    m.add_class::<ins::XorLong>()?;
+    m.add_class::<ins::ShlLong>()?;
+    m.add_class::<ins::ShrLong>()?;
+    m.add_class::<ins::UshrLong>()?;
+    m.add_class::<ins::AddFloat>()?;
+    m.add_class::<ins::SubFloat>()?;
+    m.add_class::<ins::MulFloat>()?;
+    m.add_class::<ins::DivFloat>()?;
+    m.add_class::<ins::RemFloat>()?;
+    m.add_class::<ins::AddDouble>()?;
+    m.add_class::<ins::SubDouble>()?;
+    m.add_class::<ins::MulDouble>()?;
+    m.add_class::<ins::DivDouble>()?;
+    m.add_class::<ins::RemDouble>()?;
+    m.add_class::<ins::AddInt2Addr>()?;
+    m.add_class::<ins::SubInt2Addr>()?;
+    m.add_class::<ins::MulInt2Addr>()?;
+    m.add_class::<ins::DivInt2Addr>()?;
+    m.add_class::<ins::RemInt2Addr>()?;
+    m.add_class::<ins::AndInt2Addr>()?;
+    m.add_class::<ins::OrInt2Addr>()?;
+    m.add_class::<ins::XorInt2Addr>()?;
+    m.add_class::<ins::ShlInt2Addr>()?;
+    m.add_class::<ins::ShrInt2Addr>()?;
+    m.add_class::<ins::UshrInt2Addr>()?;
+    m.add_class::<ins::AddLong2Addr>()?;
+    m.add_class::<ins::SubLong2Addr>()?;
+    m.add_class::<ins::MulLong2Addr>()?;
+    m.add_class::<ins::DivLong2Addr>()?;
+    m.add_class::<ins::RemLong2Addr>()?;
+    m.add_class::<ins::AndLong2Addr>()?;
+    m.add_class::<ins::OrLong2Addr>()?;
+    m.add_class::<ins::XorLong2Addr>()?;
+    m.add_class::<ins::ShlLong2Addr>()?;
+    m.add_class::<ins::ShrLong2Addr>()?;
+    m.add_class::<ins::UshrLong2Addr>()?;
+    m.add_class::<ins::AddFloat2Addr>()?;
+    m.add_class::<ins::SubFloat2Addr>()?;
+    m.add_class::<ins::MulFloat2Addr>()?;
+    m.add_class::<ins::DivFloat2Addr>()?;
+    m.add_class::<ins::RemFloat2Addr>()?;
+    m.add_class::<ins::AddDouble2Addr>()?;
+    m.add_class::<ins::SubDouble2Addr>()?;
+    m.add_class::<ins::MulDouble2Addr>()?;
+    m.add_class::<ins::DivDouble2Addr>()?;
+    m.add_class::<ins::RemDouble2Addr>()?;
+    m.add_class::<ins::AddIntLit>()?;
+    m.add_class::<ins::RsubIntLit>()?;
+    m.add_class::<ins::MulIntLit>()?;
+    m.add_class::<ins::DivIntLit>()?;
+    m.add_class::<ins::RemIntLit>()?;
+    m.add_class::<ins::AndIntLit>()?;
+    m.add_class::<ins::OrIntLit>()?;
+    m.add_class::<ins::XorIntLit>()?;
+    m.add_class::<ins::ShlIntLit>()?;
+    m.add_class::<ins::ShrIntLit>()?;
+    m.add_class::<ins::UshrIntLit>()?;
+    m.add_class::<ins::InvokePolymorphic>()?;
+    m.add_class::<ins::InvokeCustom>()?;
+    m.add_class::<ins::ConstMethodHandle>()?;
+    m.add_class::<ins::ConstMethodType>()?;
+    m.add_class::<ins::Try>()?;
+    m.add_class::<ins::Label>()?;
     Ok(())
 }
diff --git a/androscalpel/src/method.rs b/androscalpel/src/method.rs
index ac0f45d..9820749 100644
--- a/androscalpel/src/method.rs
+++ b/androscalpel/src/method.rs
@@ -62,6 +62,7 @@ pub struct Method {
     pub parameters_annotations: Vec<Vec<DexAnnotationItem>>,
 
     /// The code of the method
+    #[pyo3(get, set)]
     pub code: Option<Code>,
 }
 
diff --git a/androscalpel_serializer/src/value.rs b/androscalpel_serializer/src/value.rs
index 759cf04..84a1e1a 100644
--- a/androscalpel_serializer/src/value.rs
+++ b/androscalpel_serializer/src/value.rs
@@ -599,7 +599,7 @@ impl Serializable for EncodedValue {
                     .rev()
                     .take_while(|b| **b == 0)
                     .count();
-                1 + 4 - trailing_zeros
+                std::cmp::max(1 + 4 - trailing_zeros, 2)
             }
             Self::Double(val) => {
                 let trailing_zeros = val
@@ -608,7 +608,7 @@ impl Serializable for EncodedValue {
                     .rev()
                     .take_while(|b| **b == 0)
                     .count();
-                1 + 8 - trailing_zeros
+                std::cmp::max(1 + 8 - trailing_zeros, 2)
             }
             Self::MethodType(idx) => Idx(*idx, VALUE_TYPE).size(),
             Self::MethodHandle(idx) => Idx(*idx, VALUE_METHOD_HANDLE).size(),
diff --git a/test.py b/test.py
index 084143e..0a18628 100644
--- a/test.py
+++ b/test.py
@@ -8,7 +8,8 @@ import androscalpel as asc
 import zipfile as z
 from androscalpel import *
 
-APK_NAME = "test.apk"
+# APK_NAME = "test.apk"
+APK_NAME = "/home/histausse/workspace/androscalpel/apk_frauder/app-release.apk"
 DEX_NAME = "classes.dex"
 
 with z.ZipFile(APK_NAME) as zipf:
@@ -18,4 +19,32 @@ with z.ZipFile(APK_NAME) as zipf:
 apk = asc.Apk()
 apk.add_dex_file(dex)
 
+clazz_id = IdType("Lcom/example/testapplication/ui/home/HomeViewModel;")
+proto_id = IdMethodType(IdType("Ljava/lang/String;"), [])
+method_id = IdMethod("text_gen", proto_id, clazz_id)
+
+clazz = apk.classes[clazz_id]
+method = clazz.virtual_methods[method_id]
+
+print("Code of {method_id}")
+for i in method.code.insns:
+    print(i)
+
+new_insns = []
+for i in method.code.insns:
+    if isinstance(i, asc.ins.ConstString):
+        if i.lit == "Hello":
+            i.lit = DexString("Degemer Mat")
+        elif i.lit == "Bye":
+            i.lit = DexString("Kenavo")
+    new_insns.append(i)
+
+# This need improving!
+new_code = method.code
+new_code.insns = new_insns
+method.code = new_code
+clazz.virtual_methods[method_id] = method
+apk.classes[clazz_id] = clazz
+
+
 dex_raw = apk.gen_raw_dex()