old_contents: function RequiredValidator() {}
  
  Object.assign(RequiredValidator.prototype, {
    validate(value) {
      return !!value === true && value != "false";
    },
  
    errorMessage() {
      return "Required";
    }
  });
  
  export default function() {
    return new RequiredValidator();
  };
  
new_contents: function RequiredValidator() {}
  
  Object.assign(RequiredValidator.prototype, {
    validate(value) {
      return !!value === true;
    },
  
    errorMessage() {
      return "Required";
    }
  });
  
  export default function() {
    return new RequiredValidator();
  };
  
subject: Fix required validator