code: def unpack(self, buff, offset=0):
          
          super().unpack(buff, offset)
          self.wildcards = UBInt32(value=FlowWildCards.OFPFW_ALL,
                                   enum_ref=FlowWildCards)
          self.wildcards.unpack(buff, offset)
docs: Unpack *buff* into this object.
  
          Do nothing, since the _length is already defined and it is just a Pad.
          Keep buff and offset just for compability with other unpack methods.
  
          Args:
              buff (bytes): Binary buffer.
              offset (int): Where to begin unpacking.
  
          Raises:
              :exc:`~.exceptions.UnpackException`: If unpack fails.