code: def get_atoms(self, inc_alt_states=False):
          
          if inc_alt_states:
              return itertools.chain(*[x[1].values() for x in sorted(list(self.states.items()))])
          return self.atoms.values()
docs: Returns all atoms in the `Monomer`.
  
          Parameters
          ----------
          inc_alt_states : bool, optional
              If `True`, will return `Atoms` for alternate states.