code: def unpack(self, buff, offset=0):
          
          super().unpack(buff[offset:])
          self._unpack_body()
docs: Unpack a binary message into this object's attributes.
  
          Unpack the binary value *buff* and update this object attributes based
          on the results. It is an inplace method and it receives the binary data
          of the message **without the header**.
  
          This class' unpack method is like the :meth:`.GenericMessage.unpack`
          one, except for the ``body`` attribute which has its type determined
          by the ``multipart_type`` attribute.
  
          Args:
              buff (bytes): Binary data package to be unpacked, without the
                  header.