docs: def best_transcript(transcripts):
      """
      Given a set of coding transcripts, choose the one with the longest
      protein sequence and in cases of ties use the following tie-breaking
      criteria:
          - transcript sequence (including UTRs)
          - transcript name (so TP53-001 should come before TP53-202)
      """
      assert len(transcripts) > 0
      sorted_list = sorted(transcripts, key=transcript_sort_key)
      return sorted_list[0]