text: class Contract {
  
      /**
       * 
       * @param {string} mission Decription of mission
       * @param {int} reward Money reward you get of you complete mission
       * @param {int} success_rate Success rate of the mission
       * @param {date} expiration Expiration date of mission
       */
      constructor(mission, reward, success_rate, expiration) {
          this.mission = mission;
          this.reward = reward;
          this.success_rate = success_rate;
          this.expiration = expiration;
      }
  }
  
  export default Contract;