vm/bytecode.go
func (b *ByteCode) AppendOp(o OpType, args ...interface{}) Op {
	x := NewOp(o, args...)
	b.Append(x)
	return x
}
func (b *ByteCode) AppendOp(o OpType, args ...interface{}) Op {
	x := NewOp(o, args...)
	b.Append(x)
	return x
}
// AppendOp is an utility method to create AND append a new op code to the
// current list of op codes