code: def _join_modules(module1, module2):
      """Concatenate 2 module components.
  
      Args:
        module1: First module to join.
        module2: Second module to join.
  
      Returns:
        Given two modules aaa.bbb and ccc.ddd, returns a joined
        module aaa.bbb.ccc.ddd.
      """
      if not module1:
          return module2
      if not module2:
          return module1
      return "%s.%s" % (module1, module2)
  
imports: import argparse
  import collections
  import importlib
  import os
  import sys
  from tensorflow.python.tools.api.generator import doc_srcs
  from tensorflow.python.util import tf_decorator
  from tensorflow.python.util import tf_export
label_desc: Use image node_id 4 for calling a global function with example usage: _join_modules(module1, module2) and returns: unknown, module2, module1