anchor.diff:      /// that match the given predicate
       /// </summary>
       /// <param name="f">The predicate used to match elements</param>
  -    let elements f = function
  +    let elements f x =
  +        match x with
           | HtmlDocument(elements = elements) ->
               [
                   for e in elements do
  
positive.code:     /// Trys to return an attribute that exists on the current node
      /// </summary>
      /// <param name="name">The name of the attribute to return.</param>
      let tryGetAttribute (name:string) = function
          | HtmlElement(_,_,attr,_) -> attr |> List.tryFind (fun a -> a.Name.ToLowerInvariant() = (name.ToLowerInvariant()))
          | _ -> None   
      
  
negative.code: 
      type HtmlNode with
                 
          /// Gets the given nodes name
          member x.Name = HtmlNode.name x 
          
          /// Gets all of the nodes immediately under this node
          member x.Children = HtmlNode.children x
  
          /// Gets the parent node of this node
          member x.Parent = HtmlNode.parent x
  
          /// <summary>
          /// Gets all of the descendants of the current node
  