code: def fit_anonymous(self, struct1, struct2, niggli=True):
          
          struct1, struct2 = self._process_species([struct1, struct2])
          struct1, struct2, fu, s1_supercell = self._preprocess(struct1, struct2,
                                                                niggli)
  
          matches = self._anonymous_match(struct1, struct2, fu, s1_supercell,
                                          break_on_match=True, single_match=True)
  
          if matches:
              return True
          else:
              return False
docs: Performs an anonymous fitting, which allows distinct species in one
          structure to map to another. E.g., to compare if the Li2O and Na2O
          structures are similar.
  
          Args:
              struct1 (Structure): 1st structure
              struct2 (Structure): 2nd structure
  
          Returns:
              True/False: Whether a species mapping can map struct1 to stuct2