@NotNull
  private GrExpression preprocessOccurrences() {
    GroovyRefactoringUtil.sortOccurrences(myOccurrences);
    if (myOccurrences.length == 0 || !(myOccurrences[0] instanceof GrExpression)) {
      throw new IncorrectOperationException("Wrong expression occurrence");
    }

    return (GrExpression)myOccurrences[0];
  }
@NotNull
  private GrExpression preprocessOccurrences()