def is_gene_list(bed_file):
    """Check if the file is only a list of genes, not a BED
    """
    with utils.open_gzipsafe(bed_file) as in_handle:
        for line in in_handle:
            if not line.startswith("#"):
                if len(line.split()) == 1:
                    return True
                else:
                    return False
Check if the file is only a list of genes, not a BED