docs: private String performSplitting(String source, String splitString, String indexString)
          throws TransformationOperationException {
          try {
              Integer index = Integer.parseInt(indexString);
              return source.split(splitString)[index];
          } catch (NumberFormatException e) {
              throw new TransformationOperationException("The given result index parameter is not a number");
          } catch (IndexOutOfBoundsException e) {
              throw new TransformationOperationException(
                  "The split result does not have that much results for the index parameter");
          }
      }