code: def CALLCODE(self, gas, _ignored_, value, in_offset, in_size, out_offset, out_size):
          
          self.world.start_transaction('CALLCODE',
                                       address=self.address,
                                       data=self.read_buffer(in_offset, in_size),
                                       caller=self.address,
                                       value=value,
                                       gas=gas)
          raise StartTx()
docs: Message-call into this account with alternative account's code