class_docstr: Test class for common functions.
class_docstr_tok: ["Test","class","for","common","functions","."]
code: def testRegistryHelp(self):
      help_str = registry.help_string()
      self.assertIsNotNone(help_str)
      self.assertGreater(len(help_str), 0)
  
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 1 for calling the RegistryHelpTest obj's underlying member method code with example usage: obj.testRegistryHelp() without return types