class RegularizationMethod:
    """RegularizationMethod implement regularization strategies.
    RegularizationMethod is a callable.
    The method `update` is called to update the loss, typically at the end
    of an experience.
    """
    def pre_adapt(self, agent, exp):
        pass  # implementation may be empty if adapt is not needed

    def post_adapt(self, agent, exp):
        pass  # implementation may be empty if adapt is not needed

    def __call__(self, *args, **kwargs):
        raise NotImplementedError()