code: def login(self, url, use_token=True, **kwargs):
          
          response = self.post(url, **kwargs).json()
  
          if use_token:
              self.token = response['auth']['client_token']
  
          return response
docs: Perform a login request.
  
          Associated request is typically to a path prefixed with "/v1/auth") and optionally stores the client token sent
              in the resulting Vault response for use by the :py:meth:`hvac.adapters.Adapter` instance under the _adapater
              Client attribute.
  
          :param url: Path to send the authentication request to.
          :type url: str | unicode
          :param use_token: if True, uses the token in the response received from the auth request to set the "token"
              attribute on the the :py:meth:`hvac.adapters.Adapter` instance under the _adapater Client attribute.
          :type use_token: bool
          :param kwargs: Additional keyword arguments to include in the params sent with the request.
          :type kwargs: dict
          :return: The response of the auth request.
          :rtype: requests.Response