code: def fill(self, name_or_slot, value):
      
      if isinstance(name_or_slot, basestring):
        slot = getattr(self.outputs, name_or_slot)
      elif isinstance(name_or_slot, Slot):
        slot = name_or_slot
      else:
        raise UnexpectedPipelineError(
            'Could not fill invalid output name: %r' % name_or_slot)
  
      if not slot._exists:
        raise SlotNotDeclaredError(
            'Cannot fill output with name "%s" that was just '
            'declared within the Pipeline context.' % slot.name)
  
      self._context.fill_slot(self._pipeline_key, slot, value)
docs: Fills an output slot required by this Pipeline.
  
      Args:
        name_or_slot: The name of the slot (a string) or Slot record to fill.
        value: The serializable value to assign to this slot.
  
      Raises:
        UnexpectedPipelineError if the Slot no longer exists. SlotNotDeclaredError
        if trying to output to a slot that was not declared ahead of time.