code: def backend_pair(request):
      ng, nc = get_backend_pair(
          device_id=request.config.getoption("--device_id")
      )
  
      def cleanup():
          ng, nc = request.getfuncargvalue("backend_pair")
          del ng
          del nc
  
      request.addfinalizer(cleanup)
  
      return (ng, nc)
  
imports: import itertools
  import numpy
  import pytest
  import re
  import os
  import sys
  from neon.backends import gen_backend
  from neon.backends.nervanacpu import NervanaCPU
  from neon.layers.container import DeltasTree
label_desc: Use image node_id 12 for calling a global function with example usage: backend_pair(request) and returns: ng,  nc