def transcript_sort_key(transcript):
    """
    Key function used to sort transcripts. Taking the negative of
    protein sequence length and nucleotide sequence length so that
    the transcripts with longest sequences come first in the list. This couldn't
    be accomplished with `reverse=True` since we're also sorting by
    transcript name (which places TP53-001 before TP53-002).
    """
    return (
        -len(transcript.protein_sequence),
        -len(transcript.sequence),
        transcript.name
    )