code: def testNonT2TModelRegistration(self):
      @registry.register_model
      def model_fn():
          pass
  
      model = registry.model("model_fn")
      self.assertTrue(model is model_fn)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from tensor2tensor.utils import registry
  from tensor2tensor.utils import t2t_model
  import tensorflow.compat.v1
label_desc: Use image node_id 4 for calling the ModelRegistryTest obj's underlying member method code with example usage: obj.testNonT2TModelRegistration() without return types