def get_relative_cs_ratio(elemental_line, energy):
    name, line = elemental_line.split('_')
    e = Element(name)
    transition_lines = TRANSITIONS_LOOKUP[line.upper()]

    sum_v = 0
    for v in transition_lines:
        sum_v += e.cs(energy)[v]
    return e.cs(energy)[transition_lines[0]]/sum_v
At given energy, multiple elemental lines may be activated. This function is
dataset/ETHPy150Open scikit-beam/scikit-beam/skbeam/core/fitting/xrf_model.py/get_relative_cs_ratio