def add(self, elem, replace=False):
        """Add a requirement.

        :param elem: a string or :class:`Requirement` instance.
        :param replace: if `True`, packages in the set with the same name will
            be removed first.
        """
        if isinstance(elem, text_type):
            elem = Requirement.coerce(elem)
        if replace and elem in self:
            self.remove(elem)
        super(Requirements, self).add(elem)
def testDeviceWrapperSerialization(self):
    wrapper_cls = rnn_cell_wrapper_v2.DeviceWrapper
    cell = layers.LSTMCell(10)
    wrapper = wrapper_cls(cell, "/cpu:0")
    config = wrapper.get_config()

    reconstructed_wrapper = wrapper_cls.from_config(config)
    self.assertDictEqual(config, reconstructed_wrapper.get_config())
    self.assertIsInstance(reconstructed_wrapper, wrapper_cls)