@NonNls
  private static String calculateSimplifiedPrefixExpression(GrUnaryExpression expression) {
    final GrExpression operand = expression.getOperand();
    if (isUnaryNot(operand)) {
      return booleanLiteral(((GrUnaryExpression)operand).getOperand());
    }
    else {
      return negateBooleanLiteral(operand);
    }
  }
@NonNls
  private static String calculateSimplifiedPrefixExpression(GrUnaryExpression expression)