def pre_update(self, item):
        """
        Override this, this method is called before the update takes place.
        If an exception is raised by this method,
        the message is shown to the user and the update operation is
        aborted. Because of this behavior, it can be used as a way to
        implement more complex logic around updates. For instance
        allowing only the original creator of the object to update it.
        """

        Override this, this method is called before the update takes place.
        If an exception is raised by this method,
        the message is shown to the user and the update operation is
        aborted. Because of this behavior, it can be used as a way to
        implement more complex logic around updates. For instance
        allowing only the original creator of the object to update it.
        
flask_appbuilder/baseviews.py