docs: def application(self, app_id):
          """Update the context to use the given application ID and stop the
          application when done.
  
          For example::
  
              with cn.application(54):
                  # All commands in this block will use app_id=54.
                  # On leaving the block `cn.send_signal("stop", 54)` is
                  # automatically called.
          """
          # Get a new context and add a method that will be called before the
          # context is removed from the stack.
          context = self(app_id=app_id)
          context.before_close(lambda: self.send_signal("stop"))
          return context