Returns from a PSM line peptide sequence,
    and other information about the PSM.
    Return values:
        psm_id          -   str
        proteins        -   list of str

def get_pepproteins(line):
    """Returns from a PSM line peptide sequence,
    and other information about the PSM.
    Return values:
        psm_id          -   str
        proteins        -   list of str
    """
    psm_id = get_psm_id(line)
    proteins = get_proteins_from_psm(line)
    return psm_id, proteins