code: def compare_single_field(results, f1, f2, l0, l1, l2):
      if has_nan(f1) and has_nan(f2):
          results[l0] = "both NAN"
      elif has_nan(f1):
          results[l0] = "%s.%s NAN" % (l1, l0)
      elif has_nan(f2):
          results[l0] = "%s.%s NAN" % (l2, l0)
      else:
          results[l0] = "%s" % (str(rel_diff(f1, f2)))
  
imports: import unittest
  import torch
  from torch.testing._internal import common_utils
  from apex.transformer.testing.distributed_test_base import NcclDistributedTestBase
label_desc: Use image node_id 12 for calling a global function with example usage: compare_single_field(results, f1, f2, l0, l1, l2) without return types