def action(self):
        """
        Get/set the form's ``action`` attribute.
        """
        base_url = self.base_url
        action = self.get('action')
        if base_url and action is not None:
            return urljoin(base_url, action)
        else:
            return action

        Get/set the form's ``action`` attribute.
        
stackoverflow/venv/lib/python3.6/site-packages/lxml/html/__init__.py