docs: def _get_comparison_strings(self, s):
          """Find all similar strings"""
          str_len = len(s)
          comparison_idxs = make_unique_ngrams(s, self.idx_size)
          min_len = len(s) - self.plus_minus
  
          if min_len < 0:
              min_len = 0
  
          if self._els_idxed is None:
              raise UnintitializedError('Database not created')
  
          all_sets = set()
          for idx in comparison_idxs:
              found_idx = self._els_idxed.get(idx, None)
              if found_idx is None:
                  continue
              for i in range(min_len, str_len + self.plus_minus):
                  found_len = found_idx.get(i, None)
                  if found_len is not None:
                      all_sets = all_sets.union(found_len)
          return all_sets