code: public static RolloutGroup verifyRolloutGroupHasConditions(final RolloutGroup group) {
          if (group.getTargetPercentage() < 1F || group.getTargetPercentage() > 100F) {
              throw new ValidationException("Target percentage has to be between 1 and 100");
          }
  
          if (group.getSuccessCondition() == null) {
              throw new ValidationException("Rollout group is missing success condition");
          }
          if (group.getSuccessAction() == null) {
              throw new ValidationException("Rollout group is missing success action");
          }
          return group;
      }
docs: Verifies that the group has the required success condition and action and
  a falid target percentage.
  
  @param group
  the input group
  @return the verified group