# System.Xml.XPath

``` diff
 namespace System.Xml.XPath {
     [NullableAttribute((byte)0)]
     [NullableContextAttribute((byte)1)]
     public abstract class XPathNavigator : XPathItem, ICloneable, IXmlNamespaceResolver, IXPathNavigable {
-        public virtual void AppendChildElement(string prefix, string localName, string namespaceURI, string value);
+        [NullableContextAttribute((byte)2)]
+        public virtual void AppendChildElement(string? prefix, [NullableAttribute((byte)1)] string localName, string? namespaceURI, string? value);
-        public virtual void CreateAttribute(string prefix, string localName, string namespaceURI, string value);
+        [NullableContextAttribute((byte)2)]
+        public virtual void CreateAttribute(string? prefix, [NullableAttribute((byte)1)] string localName, string? namespaceURI, string? value);
-        public virtual void InsertElementAfter(string prefix, string localName, string namespaceURI, string value);
+        [NullableContextAttribute((byte)2)]
+        public virtual void InsertElementAfter(string? prefix, [NullableAttribute((byte)1)] string localName, string? namespaceURI, string? value);
-        public virtual void InsertElementBefore(string prefix, string localName, string namespaceURI, string value);
+        [NullableContextAttribute((byte)2)]
+        public virtual void InsertElementBefore(string? prefix, [NullableAttribute((byte)1)] string localName, string? namespaceURI, string? value);
-        public virtual void PrependChildElement(string prefix, string localName, string namespaceURI, string value);
+        [NullableContextAttribute((byte)2)]
+        public virtual void PrependChildElement(string? prefix, [NullableAttribute((byte)1)] string localName, string? namespaceURI, string? value);
     }
 }
```

