code: def _match(self, struct1, struct2, fu, s1_supercell=True, use_rms=False,
                 break_on_match=False):
          
          ratio = fu if s1_supercell else 1/fu
          if len(struct1) * ratio >= len(struct2):
              return self._strict_match(
                  struct1, struct2, fu, s1_supercell=s1_supercell,
                  break_on_match=break_on_match, use_rms=use_rms)
          else:
              return self._strict_match(
                  struct2, struct1, fu, s1_supercell=(not s1_supercell),
                  break_on_match=break_on_match, use_rms=use_rms)
docs: Matches one struct onto the other