code: def blacklist_token():
      
      req = flask.request.get_json(force=True)
      data = guard.extract_jwt_token(req['token'])
      blacklist.add(data['jti'])
      return flask.jsonify(message='token blacklisted ({})'.format(req['token']))
docs: Blacklists an existing JWT by registering its jti claim in the blacklist.
  
      .. example::
         $ curl http://localhost:5000/blacklist_token -X POST \
           -d '{"token":"<your_token>"}'