static boolean isIteratorNextDeclaration(
    PsiStatement statement, PsiVariable iterator,
    PsiType contentType) {
    if (!(statement instanceof PsiDeclarationStatement declarationStatement)) {
      return false;
    }
    final PsiElement[] declaredElements =
      declarationStatement.getDeclaredElements();
    if (declaredElements.length != 1) {
      return false;
    }
    final PsiElement declaredElement = declaredElements[0];
    if (!(declaredElement instanceof PsiVariable variable)) {
      return false;
    }
    final PsiExpression initializer = variable.getInitializer();
    return isIteratorNext(initializer, iterator, contentType);
  }
static boolean isIteratorNextDeclaration(
    PsiStatement statement, PsiVariable iterator,
    PsiType contentType)