def make_transcript_gene_se(fn):
    """
    Make a Pandas Series with transcript ID's as the index and values as the
    gene ID containing that transcript.

    Parameters
    ----------
    fn : str
        Filename of the Gencode gtf file.

    Returns
    -------
    se : pandas.Series
        Make a Pandas Series with transcript ID's as the index and values as the
        gene ID containing that transcript.

    """
    import itertools as it

    import HTSeq

    gtf = it.islice(HTSeq.GFF_Reader(fn), None)
    transcripts = []
    genes = []
    line = gtf.next()
    while line != '':
        if line.type == 'transcript':
            transcripts.append(line.attr['transcript_id'])
            genes.append(line.attr['gene_id'])
        try:
            line = gtf.next()
        except StopIteration:
            line = ''
   
    return pd.Series(genes, index=transcripts)
Make a Pandas Series with transcript ID's as the index and values as the
    gene ID containing that transcript.

    Parameters
    ----------
    fn : str
        Filename of the Gencode gtf file.

    Returns
    -------
    se : pandas.Series
        Make a Pandas Series with transcript ID's as the index and values as the
        gene ID containing that transcript.