docs: def filter_known_searchspace(elements, seqtype, lookup, ns, ntermwildcards,
                               deamidation):
      """Yields peptides from generator as long as their sequence is not found in
      known search space dict. Useful for excluding peptides that are found in
      e.g. ENSEMBL or similar"""
      for element in elements:
          seq_is_known = False
          for seq in get_seqs_from_element(element, seqtype, ns, deamidation):
              if lookup.check_seq_exists(seq, ntermwildcards):
                  seq_is_known = True
                  break
          if seq_is_known:
              formatting.clear_el(element)
          else:
              yield formatting.string_and_clear(element, ns)