class_docstr: Test of base registry.Registry class.
class_docstr_tok: ["Test","of","base","registry.Registry","class","."]
code: def testDefaultKeyFn(self):
      r = registry.Registry(
          "test", default_key_fn=lambda x: x().upper()
      )
      r.register()(lambda: "hello")
      self.assertEqual(r["HELLO"](), "hello")
  
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 2 for calling the RegistryClassTest obj's underlying member method code with example usage: obj.testDefaultKeyFn() without return types