code: def default():
      
      credentials = _utils.get_credentials()
      if Context._global_context is None:
        project = _project.Projects.get_default_id(credentials)
        Context._global_context = Context(project, credentials)
      else:
        # Always update the credentials in case the access token is revoked or expired
        Context._global_context.set_credentials(credentials)
      return Context._global_context
docs: Retrieves a default Context object, creating it if necessary.
  
        The default Context is a global shared instance used every time the default context is
        retrieved.
  
        Attempting to use a Context with no project_id will raise an exception, so on first use
        set_project_id must be called.
  
      Returns:
        An initialized and shared instance of a Context object.