def not_pepxml(tmp_path):
    """Create a file that is not a PepXML."""
    out_file = str(tmp_path / "test.tsv")
    with open(out_file, "w+") as out_ref:
        out_ref.write(r"Blah\tblah\blah\nblah\tblah\blah\n")

    return out_file