def helper_twoarg_invtrig(f, unit1, unit2):
    from ..si import radian
    (converters, _) = get_converters_and_unit(f, unit1, unit2)
    return (converters, radian)
def helper_twoarg_invtrig(f, unit1, unit2):
    from ..si import radian
    (converters, _) = get_converters_and_unit(f, unit1, unit2)
    return (converters, radian)