code: def spmm_add(src, edge_index, size, flow="target_to_source"):
      adj_indices = tf.stack([edge_index[0], edge_index[1]], axis=1)
      adj_values = tf.ones(tf.shape(edge_index)[1])
      adj_shape = size
      adj = tf.SparseTensor(
          tf.cast(adj_indices, tf.int64), adj_values, adj_shape
      )
      adj = tf.sparse_reorder(adj)
      return tf.sparse_tensor_dense_matmul(adj, src)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import tensorflow
label_desc: Use image node_id 1 for calling a global function with example usage: spmm_add(src, edge_index, size, flow) and returns: tf