def METHOD_NAME(self, energy=None):
    """Calculate wavelength from energy
    Args:
        energy(float): Energy [keV]
    Returns:
        (float): wavelength [Å]
    """
    energy = energy or self.get_value()
    # TODO NBNB This is naughty. Coud  we not put the heuristic switch
    #  in the calling functions, to avoid surprises?
    #  rhfogh 20210826
    # energy in KeV to get wavelength in Å
    energy = energy / 1000.0 if energy > 1000 else energy
    return HC_OVER_E / energy