@ValidateLarchPlugin
def mu_chantler(element, energy, incoh=False, photo=False, _larch=None):
    xdb = get_xraydb(_larch)
    col = 'mu_total'
    if photo: col = 'mu_photo'
    if incoh: col = 'mu_incoh'
    return xdb._getChantler(element, energy, column=col)
returns x-ray mass attenuation coefficient, mu/rho, for a
dataset/ETHPy150Open xraypy/xraylarch/plugins/xray/xraydb_plugin.py/mu_chantler