def _gene_length(htseq_genomic_feature):
    """
    Get feature length
    :param htseq_genomic_feature: HTSeq.GenomeFeature
        GenomeFeature from a GFF_Reader iterable
    :return: int
        Feature length
    """
    return abs(htseq_genomic_feature.iv.start - htseq_genomic_feature.iv.end)