anchor.diff:      return builder.namespaces[uri];
     }
   
  -  // Internal method to add something to the current element.
  +  // Internal method to add children to the current element.
     void _insert(Object value) {
       if (value is Function) {
         value();
  
positive.code:   /**
     * Binds a namespace `prefix` to the provided `uri`. The `prefix` can be
     * omitted to declare a default namespace. Throws an [ArgumentError] if
     * the `prefix` conflicts with an existing delcaration.
     */
    void namespace(String uri, [String prefix]) {
      if (prefix == _XMLNS || prefix == _XML) {
  
negative.code:     }
    }
  
  }
  
  abstract class _XmlNodeBuilder {
  