code: def difference(self, other, sort=None):
          self._validate_sort_keyword(sort)
          self._assert_can_do_setop(other)
          if self.equals(other):
              return self._shallow_copy(self._data[:0])
          other, result_name = self._convert_can_do_setop(other)
          this = self._get_unique_index()
          indexer = this.get_indexer(other)
          indexer = indexer.take((indexer != -1).nonzero()[0])
          label_diff = np.setdiff1d(np.arange(this.size), indexer,
                                    assume_unique=True)
          the_diff = this.values.take(label_diff)
          if sort is None:
              try:
                  the_diff = sorting.safe_sort(the_diff)
              except TypeError:
                  pass
          return this._shallow_copy(the_diff, name=result_name, freq=None)