code: def add_deferred_effect(self, effect, pos):
          
          if not isinstance(pos, (unicode, str)):
              raise Exception("Invalid POS tag. Must be string not %d" % (type(pos)))
          if self['speaker_model']['is_syntax_stacked'] == True:
              self.__dict__['deferred_effects'].insert(0,(pos, effect,))
          elif self['speaker_model']['is_syntax_stacked'] == False:
              self.__dict__['deferred_effects'].append((pos, effect,))
          else:
              raise Contradiction("Speaker Model undefined")
docs: Pushes an (pos, effect) tuple onto a stack to later be executed if the
          state reaches the 'pos'.