def request(self, filter=None):
        """Retrieve running configuration and device state information.

        *filter* specifies the portion of the configuration to retrieve (by default entire configuration is retrieved)

        :seealso: :ref:`filter_params`
        """
        node = new_ele("get")
        if filter == None:
            node.append(util.build_filter(filter))
        return self._request(node)
dataset/ETHPy150Open osrg/ryu/ryu/contrib/ncclient/operations/retrieve.py/Get.request/operator `is not` -> `==`