def _get_calling_node(self, prev_ctx=None):
        if prev_ctx is None:
            thread_id = PyThread_get_thread_ident()
            try:
                prev_ctx = _current_contexts[thread_id]
            except __HOLE__:
                prev_ctx = None

            if prev_ctx is None:
                prev_ctx = self

        if len(prev_ctx._node_eval_stack) > 0:
            return prev_ctx._node_eval_stack[-1]

        return None
dataset/ETHPy150Open manahl/mdf/mdf/context.py/MDFContext._get_calling_node