anchor.diff:  
   type FSharpLazy = 
       static member Create (v: _ Func) = Lazy.Create v.Invoke
  -    static member CreateFromValue v = Lazy.CreateFromValue v
  +    static member CreateFromValue v = Lazy.CreateFromValue v
positive.code: 
      [<Extension>]
      static member Ap (f: Choice<Func<_,_>, _>, x) =
        f
        |> Choice.map (fun a -> a.Invoke)
        |> Choice.ap x
  
      // validation
  
  
negative.code:         List.choose chooser.Invoke l
  
      [<Extension>]
      static member TryFind (l, pred: _ Predicate) = 
          List.tryFind pred.Invoke l
  
      [<Extension>]
      static member TryFind (l, value) = 
          List.tryFind ((=) value) l
  
      [<Extension>]
      static member Cons (l, e) = e::l
  
      static member Create([<ParamArray>] values: 'a array) =
  