code: def setup(self, builder):
          
          builder.components.add_components(self.transitions)
          self.random = builder.randomness.get_stream(self.key)
docs: Performs this component's simulation setup and return sub-components.
  
          Parameters
          ----------
          builder : `engine.Builder`
              Interface to several simulation tools including access to common random
              number generation, in particular.
  
          Returns
          -------
          iterable
              This component's sub-components.