code: def setup(self, builder):
          
          builder.components.add_components(self.states)
          self.population_view = builder.population.get_view([self.state_column])
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.