new_contents: from devicehive.transport import Request
  from devicehive.transport import Response
  
  
  class Api(object):
      """Api class."""
  
      def __init__(self, transport):
          self._transport = transport
  
      def _request(self, url, action, request, **params):
          req = Request(url, action, request, **params)
          response = self._transport.request(req.action(), req.request(),
                                             **req.params())
          return Response(response)
  
      def refresh_token(self, refresh_token):
          url = 'token/refresh'
          action = url
          request = {'refreshToken': refresh_token}
          params = {'method': 'POST',
                    'merge_data': True}
          return self._request(url, action, request, **params)
  
subject: Add Api class with refresh token request