Proxy to :class:`google.cloud.datastore.key.Key`.

        Passes our ``project``.

def key(self, *path_args, **kwargs):
        """Proxy to :class:`google.cloud.datastore.key.Key`.

        Passes our ``project``.
        """
        if "project" in kwargs:
            raise TypeError("Cannot pass project")
        kwargs["project"] = self.project
        if "namespace" not in kwargs:
            kwargs["namespace"] = self.namespace
        return Key(*path_args, **kwargs)