code: public Object valueAtIn(int index, List aList) {
          if (aList.size() > index) {
              return aList.get(index);
          } else {
              throw new SlimFixtureException(false, "list only has " + aList.size() + " elements");
          }
      }
docs: Retrieves element at index (0-based).
  @param index 0-based index of element to retrieve value of.
  @param aList list to get element value from.
  @return element at specified index.
  @throws SlimFixtureException if the list does not have at least index elements.