def __init__(self, groups=None):
        super(GroupedRequirements, self).__init__(NamedRequirements)
        self.groups = groups or self.default_groups
        self.filename = None
        self.create_default_groups()
def get_target_input(module, input, output):
    """A forward hook which saves the tensor - attached to its graph.
    Used if we want to explain the interim outputs of a model
    """
    try:
        del module.target_input
    except AttributeError:
        pass
    setattr(module, 'target_input', input)