code: def get_alignment_stream(self, plate=None, plate_value=None):
          
          if not self.alignment_node:
              return None
          if plate is not None or plate_value is not None:
              # TODO: Need to implement alignment nodes that live inside plates
              raise NotImplementedError("Currently only alignment nodes outside of plates are supported")
          return self.alignment_node.streams[plate]
docs: Gets the alignment stream for a particular plate value
  
          :param plate: The plate on which the alignment node lives
          :param plate_value: The plate value to select the stream from the node
          :return: The alignment stream