code: def similar_keys(self, key, replaces):
          
          return self._similar_keys("", key, self.dct.ROOT, replaces)
docs: Returns all variants of ``key`` in this DAWG according to
          ``replaces``.
  
          ``replaces`` is an object obtained from
          ``DAWG.compile_replaces(mapping)`` where mapping is a dict
          that maps single-char unicode sitrings to another single-char
          unicode strings.
  
          This may be useful e.g. for handling single-character umlauts.