code: def get_request_token(self, request, callback):
          
          callback = force_text(request.build_absolute_uri(callback))
          try:
              response = self.request('post', self.request_token_url, oauth_callback=callback)
              response.raise_for_status()
          except RequestException as e:
              logger.error('Unable to fetch request token: {0}'.format(e))
              return None
          else:
              return response.text
docs: Fetch the OAuth request token. Only required for OAuth 1.0.