Flat list of all the Atoms in the Polymer.

        Parameters
        ----------
        inc_alt_states : bool
            If true atoms from alternate conformations are included rather
            than only the "active" states.

        Returns
        -------
        atoms : itertools.chain
            Returns an iterator of all the atoms. Convert to list if you
            require indexing.

def get_atoms(self, ligands=True, inc_alt_states=False):
        """Flat list of all the Atoms in the Polymer.

        Parameters
        ----------
        inc_alt_states : bool
            If true atoms from alternate conformations are included rather
            than only the "active" states.

        Returns
        -------
        atoms : itertools.chain
            Returns an iterator of all the atoms. Convert to list if you
            require indexing.
        """
        if ligands and self.ligands:
            monomers = self._monomers + self.ligands._monomers
        else:
            monomers = self._monomers
        atoms = itertools.chain(
            *(list(m.get_atoms(inc_alt_states=inc_alt_states)) for m in monomers))
        return atoms