@Contract("null -> null")
  static @Nullable String getOperatorText(@Nullable PsiElement element) {
    if (element instanceof PsiUnaryExpression) {
      return ((PsiUnaryExpression)element).getOperationSign().getText();
    }
    return null;
  }
@Contract("null -> null")
  static @Nullable String getOperatorText(@Nullable PsiElement element)