code: function get_authorization_request(authorization_request_id) {
      return new Promise((resolve, reject) => {
          dbMgr
              .find("authorization_request", {
                  _id: {
                      $eq: authorization_request_id
                  }
              }, {limit: 1})
              .then((authorize_requests) => {
                  if (authorize_requests.length > 0) {
                      return resolve(authorize_requests[0]);
                  } else {
                      return reject(new Error("No authorization request records found!"));
                  }
              }, reject);
      });
  }
docs: This function must return a promise, which resolves with the
  authorization_request associated with the authorization_request_id argument.
  
  Also, the implementation must check for the time the respective
  authorization_request was granted, and reject the promise if the persisted
  and/or granted authorizeRequest is older than some configurable duration.
  
  @param  authorization_request_id: the authorization_code is used as the id
  in this implementation.
  @return {[object]}