code: def add_space_nonlocal(input, dim_in, dim_out, prefix, dim_inner):
      """
      add_space_nonlocal:
          Non-local Neural Networks: see https://arxiv.org/abs/1711.07971
      """
      conv = space_nonlocal(input, dim_in, dim_out, prefix, dim_inner)
      output = fluid.layers.elementwise_add(
          input, conv, name=prefix + "_sum"
      )
      return output
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from __future__ import unicode_literals
  import paddle.fluid
  from paddle.fluid import ParamAttr
label_desc: Use image node_id 2 for calling a global function with example usage: add_space_nonlocal(input, dim_in, dim_out, prefix, dim_inner) and returns: output