def METHOD_NAME(filedata):
    HEAD_FIX = dict(
        num_head_lines=93,
        num_head_fmt=1001,
        data_originator="Brem, Benjamin; Baltensperger, Urs",
        sponsor_organisation="CH02L, Paul Scherrer Institut, PSI, Laboratory of Atmospheric Chemistry (LAC), OFLB, , 5232, Villigen PSI, Switzerland",
        submitter="Brem, Benjamin",
        project_association="ACTRIS CREATE EMEP GAW-WDCA",
        vol_num=1,
        vol_totnum=1,
        ref_date=np.datetime64("2019-01-01T00:00:00"),
        revision_date=np.datetime64("2021-05-28T00:00:00"),
        freq=0.041667,
        descr_time_unit="days from file reference point",
        num_cols_dependent=23,
        mul_factors=[1.0] * 23,
        vals_invalid=[999.999999, 9999.99, 999.99, 9999.99]
        + [99.99999999] * 9
        + [999.99999999] * 9
        + [9.999999],
        descr_first_col="end_time of measurement, days from the file reference point",
    )
    assert isinstance(filedata.head_fix, dict)
    assert filedata.head_fix == HEAD_FIX