def METHOD_NAME(self, msg):
    """This is the inverse method for reduce.
    Args:
        feature (paddle.Tensor): A reduced message. 
    Returns:
        Returns a paddle.Tensor with the first dim the same as the num_edges.
    Examples:
        .. code-block:: python
            import numpy as np
            import pgl
            import paddle
            num_nodes = 5
            edges = [ (0, 1), (1, 2), (3, 4)]
            feature = np.random.randn(5, 100)
            edge_feature = np.random.randn(3, 100)
            graph = pgl.Graph(num_nodes=num_nodes,
                    edges=edges,
                    node_feat={
                        "feature": feature
                    },
                    edge_feat={
                        "edge_feature": edge_feature
                    })
            graph.tensor() 
            def send_func(src_feat, dst_feat, edge_feat):
                return { "out": src_feat["feature"] }
            message = graph.send(send_func, src_feat={"feature": graph.node_feat["feature"]})
            def recv_func(msg):
                value = msg["out"]
                max_value = msg.reduce_max(value)
                # We want to subscribe the max_value correspond to the destination node.
                max_value = msg.edge_expand(max_value)
                value = value - max_value
                return msg.reduce_sum(value)
            out = graph.recv(recv_func, message)
    """
    return paddle.gather(msg, self._segment_ids, axis=0)