def _finalized(self):
        """
        Return true if all dependencies have informed this node that they'll
        be sending no more data (by calling _finalize()), and that they have
        sent at least one batch of data (by calling enqueue())
        """
        return \
            len(self._finalized_dependencies) >= self.dependency_count \
            and len(self._enqueued_dependencies) >= self.dependency_count