code: def get_access_token(self, code):
          
          self.token = self.oauth.fetch_token(
              token_url=self.access_token_url,
              client_id=self.client_id,
              client_secret=self.client_secret,
              scope=self.scope,
              code=code
          )
          return self.token.get("access_token")
docs: Getting access token
          :param code [string]: The authorization code supplied to the callback by Unsplash.
          :return [string]: access token