code: def add_template_global(self, func: Callable, name: Optional[str]=None) -> None:
          
          self.jinja_env.globals[name or func.__name__] = func
docs: Add a template global.
  
          This is designed to be used on the application directly. An
          example usage,
  
          .. code-block:: python
  
              def five():
                  return 5
  
              app.add_template_global(five)
  
          Arguments:
              func: The function that is the global.
              name: The global name (defaults to function name).