@Nullable
  private static GrExpression getLast(GrExpression[] oldArgs) {
    GrExpression anchor;
    if (oldArgs.length > 0) {
      anchor = oldArgs[oldArgs.length - 1];
    }
    else {
      anchor = null;
    }
    return anchor;
  }
@Nullable
  private static GrExpression getLast(GrExpression[] oldArgs)