def get_diff(b):
    return b['b2'].subtract(b['b1']).select(['sur_refl_b02'], ['b1'])
testing when we pass cdata to the xml
dataset/ETHPy150Open nasa/CrisisMappingToolkit/cmt/modis/simple_modis_algorithms.py/get_diff--crossover with--dataset/ETHPy150Open abunsen/Paython/tests/test_utils.py/test_cdata_parse_xml