diff --git a/src/converters.js b/src/converters.js
index 2b80623..c0661a6 100644
--- a/src/converters.js
+++ b/src/converters.js
@@ -420,7 +420,7 @@ export function cleanList( evt, data, conversionApi ) {
 
 		for ( const child of children ) {
 			if ( !child.is( 'li' ) ) {
-				child.remove();
+				child._remove();
 			}
 		}
 	}
@@ -447,7 +447,7 @@ export function cleanListItem( evt, data, conversionApi ) {
 
 		for ( const child of children ) {
 			if ( foundList && !child.is( 'ul' ) && !child.is( 'ol' ) ) {
-				child.remove();
+				child._remove();
 			}
 
 			if ( child.is( 'text' ) ) {
@@ -779,7 +779,7 @@ export function modelIndentPasteFixer( evt, [ content, selection ] ) {
 			if ( indentChange > 0 ) {
 				// Adjust indent of all "first" list items in inserted data.
 				while ( item && item.is( 'listItem' ) ) {
-					item.setAttribute( 'indent', item.getAttribute( 'indent' ) + indentChange );
+					item._setAttribute( 'indent', item.getAttribute( 'indent' ) + indentChange );
 
 					item = item.nextSibling;
 				}
@@ -798,7 +798,7 @@ function generateLiInUl( modelItem, conversionApi ) {
 	const viewItem = createViewListItemElement();
 
 	const viewList = viewWriter.createContainerElement( listType, null );
-	viewList.appendChildren( viewItem );
+	viewList._appendChildren( viewItem );
 
 	mapper.bindElements( modelItem, viewItem );
 
diff --git a/tests/listengine.js b/tests/listengine.js
index 5af3df6..85f989e 100644
--- a/tests/listengine.js
+++ b/tests/listengine.js
@@ -3390,7 +3390,7 @@ describe( 'ListEngine', () => {
 			const uiElement = new ViewUIElement( 'span' );
 
 			// Append ui element at the end of first <li>.
-			viewDoc.getRoot().getChild( 0 ).getChild( 0 ).appendChildren( [ uiElement ] );
+			viewDoc.getRoot().getChild( 0 ).getChild( 0 )._appendChildren( [ uiElement ] );
 
 			expect( getViewData( editor.editing.view, { withoutSelection: true } ) )
 				.to.equal( '<ul><li>Foo<span></span></li><li>Bar</li></ul>' );
@@ -3412,7 +3412,7 @@ describe( 'ListEngine', () => {
 			const uiElement = new ViewUIElement( 'span' );
 
 			// Append ui element at the end of first <li>.
-			viewRoot.getChild( 0 ).getChild( 0 ).appendChildren( [ uiElement ] );
+			viewRoot.getChild( 0 ).getChild( 0 )._appendChildren( [ uiElement ] );
 
 			expect( getViewData( editor.editing.view, { withoutSelection: true } ) )
 				.to.equal( '<ul><li>Foo<span></span></li><li>Bar<ul><li>Xxx</li><li>Yyy</li></ul></li></ul>' );
@@ -3440,7 +3440,7 @@ describe( 'ListEngine', () => {
 
 			it( 'ui element before <ul>', () => {
 				// Append ui element before <ul>.
-				viewRoot.insertChildren( 0, [ uiElement ] );
+				viewRoot._insertChildren( 0, [ uiElement ] );
 
 				model.change( writer => {
 					writer.remove( liFoo );
@@ -3452,7 +3452,7 @@ describe( 'ListEngine', () => {
 
 			it( 'ui element before first <li>', () => {
 				// Append ui element before <ul>.
-				viewRoot.getChild( 0 ).insertChildren( 0, [ uiElement ] );
+				viewRoot.getChild( 0 )._insertChildren( 0, [ uiElement ] );
 
 				model.change( writer => {
 					writer.remove( liFoo );
@@ -3464,7 +3464,7 @@ describe( 'ListEngine', () => {
 
 			it( 'ui element in the middle of list', () => {
 				// Append ui element before <ul>.
-				viewRoot.getChild( 0 ).insertChildren( 1, [ uiElement ] );
+				viewRoot.getChild( 0 )._insertChildren( 1, [ uiElement ] );
 
 				model.change( writer => {
 					writer.remove( liBar );
diff --git a/tests/utils.js b/tests/utils.js
index 15e61c0..fcd0247 100644
--- a/tests/utils.js
+++ b/tests/utils.js
@@ -30,19 +30,19 @@ describe( 'utils', () => {
 
 			it( 'should return 0 if item has only lists as children', () => {
 				const innerListItem1 = createViewListItemElement();
-				innerListItem1.appendChildren( new ViewText( 'foo' ) );
+				innerListItem1._appendChildren( new ViewText( 'foo' ) );
 				const innerListItem2 = createViewListItemElement();
-				innerListItem2.appendChildren( new ViewText( 'bar' ) );
+				innerListItem2._appendChildren( new ViewText( 'bar' ) );
 				const innerList = new ViewContainerElement( 'ul', null, [ innerListItem1, innerListItem2 ] );
 				const outerListItem = createViewListItemElement();
-				outerListItem.appendChildren( innerList );
+				outerListItem._appendChildren( innerList );
 
 				expect( outerListItem.getFillerOffset() ).to.equal( 0 );
 			} );
 
 			it( 'should return null if item has non-list contents', () => {
 				const item = createViewListItemElement();
-				item.appendChildren( new ViewText( 'foo' ) );
+				item._appendChildren( new ViewText( 'foo' ) );
 
 				expect( item.getFillerOffset() ).to.be.null;
 			} );