diff --git a/compiler/compiler.go b/compiler/compiler.go
index c8d4e91..93016ae 100644
--- a/compiler/compiler.go
+++ b/compiler/compiler.go
@@ -50,6 +50,27 @@ func (compiler *Compiler) assemble(addNone bool) *gython.CodeObject {
 	}
 
 	codeobject := gython.NewCodeObject([]byte{}, []byte{}, 0)
+	for _, instr := range compiler.currentScope.Instructions {
+		arg := 0
+		ext := 0
+		size := instr.Size()
+		if instr.Hasarg {
+			arg = int(instr.Oparg.Value)
+			ext = arg >> 16
+		}
+
+		if size == 6 {
+			codeobject.AppendOpcode(bytecode.EXTENDED_ARG)
+			codeobject.AppendInt(ext & 0xff)
+			codeobject.AppendInt(ext >> 8)
+			arg &= 0xffff
+		}
+		codeobject.AppendOpcode(instr.Opcode)
+		if instr.Hasarg {
+			codeobject.AppendInt(arg & 0xff)
+			codeobject.AppendInt(arg >> 8)
+		}
+	}
 	return codeobject
 }
 
diff --git a/compiler/instruction.go b/compiler/instruction.go
index 48f126c..ca6e4a2 100644
--- a/compiler/instruction.go
+++ b/compiler/instruction.go
@@ -20,3 +20,15 @@ func NewInstruction(opcode bytecode.Opcode, oparg *gython.Float, hasarg bool) *I
 		Line:   0,
 	}
 }
+
+func (instruction *Instruction) Size() int {
+	if instruction.Hasarg == false {
+		// 1 byte for the opcode
+		return 1
+	} else if instruction.Oparg.Value > 0xffff {
+		// 1 (opcode) + 1 (EXTENDED_ARG opcode) + 2 (oparg) + 2(oparg extended)
+		return 6
+	}
+	// 1 (opcode) + 2 (oparg)
+	return 3
+}
diff --git a/gython/bytes.go b/gython/bytes.go
index 2090d1d..8a9bece 100644
--- a/gython/bytes.go
+++ b/gython/bytes.go
@@ -1,10 +1,22 @@
 package gython
 
 type Bytes struct {
+	value []byte
 }
 
-func (bytes *Bytes) object() {}
-
 func NewBytes() *Bytes {
-	return &Bytes{}
+	return &Bytes{
+		value: make([]byte, 0),
+	}
+}
+
+func (bytes *Bytes) object() {}
+func (bytes *Bytes) Append(b byte) {
+	bytes.value = append(bytes.value, b)
+}
+func (bytes *Bytes) String() string {
+	return string(bytes.value)
+}
+func (bytes *Bytes) Value() []byte {
+	return bytes.value
 }
diff --git a/gython/codeobject.go b/gython/codeobject.go
index 0319d6e..b6d7b2a 100644
--- a/gython/codeobject.go
+++ b/gython/codeobject.go
@@ -1,5 +1,7 @@
 package gython
 
+import "github.com/brettlangdon/gython/bytecode"
+
 type CodeObject struct {
 	ArgCount            int
 	KeywordOnlyArgCount int
@@ -43,3 +45,9 @@ func NewCodeObject(filename []byte, name []byte, firstLineNumber int) *CodeObjec
 }
 
 func (codeobject *CodeObject) object() {}
+func (codeobject *CodeObject) AppendOpcode(op bytecode.Opcode) {
+	codeobject.Code.Append(byte(op))
+}
+func (codeobject *CodeObject) AppendInt(i int) {
+	codeobject.Code.Append(byte(i))
+}