def __init__(self, function, output_shape=None, arguments={}, **kwargs):
        self.function = function
        self.arguments = arguments
        if output_shape is None:
            self._output_shape = None
        elif type(output_shape) is not {tuple, list}:
            self._output_shape = tuple(output_shape)
        else:
            if not hasattr(output_shape, '__call__'):
                raise Exception('In Lambda, `output_shape` '
                                'must be a list, a tuple, or a function.')
            self._output_shape = output_shape
        super(Lambda, self).__init__(**kwargs)
dataset/ETHPy150Open fchollet/keras/keras/layers/core.py/Lambda.__init__/operator `in` -> `is not`