docs: protected Integer getNonNegativeIntegerFromLiteralPathElement() {
  
          Integer pathElementInt = null;
  
          try {
              pathElementInt = Integer.parseInt( pathElement.getRawKey() );
  
              if ( pathElementInt < 0 ) {
                  return null;
              }
          }
          catch( NumberFormatException nfe ) {
              // If the data is an Array, but the spec keys are Non-Integer Strings,
              //  we are annoyed, but we don't stop the whole transform.
              // Just this part of the Transform won't work.
          }
  
          return pathElementInt;
      }