*Experimental:* Copies a resource from a Docker container to a local tar file. For details, see
        :meth:`docker.client.Client.copy`.

        :param container: Container name or id.
        :type container: unicode | str
        :param resource: Resource inside the container.
        :type resource: unicode | str
        :param local_filename: Local file to store resource into. Will be overwritten if present.
        :type local_filename: unicode | str

def copy_resource(self, container, resource, local_filename):
        """
        *Experimental:* Copies a resource from a Docker container to a local tar file. For details, see
        :meth:`docker.client.Client.copy`.

        :param container: Container name or id.
        :type container: unicode | str
        :param resource: Resource inside the container.
        :type resource: unicode | str
        :param local_filename: Local file to store resource into. Will be overwritten if present.
        :type local_filename: unicode | str
        """
        raw = self.copy(container, resource)
        with open(local_filename, 'wb+') as f:
            for buf in raw:
                f.write(buf)