def append_p1c1_date_table(dump_fname,
                           p1c1_date_table):
    """
    Append lines "# P1-C1 [m]: G{prn}: {p1c1_bias}" (in [m]) to
    *dump_fname* from the information found in
    *p1c1_date_table*. Return *dump_fname*.
    """
    with open(dump_fname, 'a') as fid:
        for prn in sorted(p1c1_date_table['prn']):
            fid.write('# P1-C1 [m]: G{:02d}: '
                      '{:8.3f}\n'.format(prn, p1c1_date_table['prn'][prn]))
    return dump_fname