code: @Override
      public <T> T getValue(String key) {
          ValueObject vo = get(key);
          if (null == vo) {
              return null;
          }
          return vo.value();
      }
docs: Get {@link ValueObject#value() value object value} by key from the
  store.
  @param key the key
  @param <T> the generic type of the return value
  @return the value stored in the value object associated with the key
  @see ValueObject#value()