import tensorflow as tf

  Return:
    A tuple of list: (nodes, adjcents)
      nodes: A list of N + 1 `tf.Tensor` of `int64`, N is the number of
        hops. Specify node set of each hop, including the root.
      adjcents: A list of N `tf.SparseTensor` of `int64`. Specify adjacent
        matrix between hops.
  """
  nodes = tf.reshape(nodes, [-1])
  nodes_list = [nodes]
  adj_list = []
  for hop_edge_types in edge_types:
    neighbor, weight, _ = get_full_neighbor(nodes, hop_edge_types)
    next_nodes, next_idx = tf.unique(neighbor.values, out_idx=tf.int64)
    next_indices = tf.stack([neighbor.indices[:, 0], next_idx], 1)
