def METHOD_NAME(self, a, b):
    """
    https://github.com/synfig/synfig/blob/15607089680af560ad031465d31878425af927eb/ETL/ETL/_curve_func.h#L56
    Args:
        a (Template T):
        b (Template T):
    Returns:
        (T)
    """
    delta = b - a
    return delta*delta