code: def connect(self, output_name, input_method):
          
          src, outbox = self._compound_outputs[output_name]
          self._compound_children[src].connect(outbox, input_method)
docs: Connect an output to any callable object.
  
          :param str output_name: the output to connect. Must be one of
              the ``'self'`` outputs in the ``linkages`` parameter.
  
          :param callable input_method: the thread-safe callable to invoke
              when :py:meth:`send` is called.