code: public void setValidUsageModes(Collection<DataUsage> validUsageModes) throws PropertyException {
          Validate.notNull(validUsageModes);
          if (validUsageModes.isEmpty()) {
              return;
          }
          Validate.noNullElements(validUsageModes);
          Set<DataUsage> usageSet = new HashSet<DataUsage>(validUsageModes);
          setProperty(ACModelProperty.VALID_USAGE_MODES, ArrayUtils.toString(encapsulateValues(usageSet)));
      }
docs: -- Valid usage modes