code: def remove_undocumented(module_name, allowed_symbols):
      """Removes symbols in a module that are not referenced by a docstring.
  
      Args:
        module_name: the name of the module (usually `__name__`).
        allowed_symbols: which symbols are allowed for this module.
  
      Returns:
        None
      """
      current_symbols = set(dir(sys.modules[module_name]))
      extra_symbols = current_symbols - set(allowed_symbols)
      target_module = sys.modules[module_name]
      for extra_symbol in extra_symbols:
          # Skip over __file__, etc. Also preserves internal symbols.
          if extra_symbol.startswith("_"):
              continue
          fully_qualified_name = module_name + "." + extra_symbol
          _HIDDEN_ATTRIBUTES[fully_qualified_name] = (
              target_module,
              getattr(target_module, extra_symbol),
          )
          delattr(target_module, extra_symbol)
  
label_desc: Use image node_id 1 for calling a global function with example usage: remove_undocumented(module_name, allowed_symbols) without return types