anchor.diff:  type Any private() =
       static let regs = Runner.init.Force()
   
  -    ///Build a generator that generates a value from one of the generators in the given non-empty IEnumerable, with
  -    ///equal probability.
  -    static member private OneOfSeqGen gs = 
  -        gs |> Seq.toList |> oneof
  -
  -    ///Build a generator that randomly generates one of the values in the given non-empty IEnumerable.
  -    static member private OneOfSeqValue vs = 
  -        vs |> Seq.toList |> elements
  -
       ///Sequence the given list of generators into a generator of a list.
       static member private SequenceSeq<'a> gs = 
           gs |> Seq.toList |> sequence |> map (fun list -> new List<'a>(list))
  
positive.code:     ///Build a generator that generates a value from one of the constants in the given non-empty seq, with
      ///given probabilities. The sum of the probabilities must be larger than zero.
      static member private OneOfWeighedSeqValue ws = 
          ws |> Seq.map (fun wv -> (wv.Weight, constant wv.Value)) |> Seq.toList |> frequency
  
      ///Build a generator that generates a value from one of the generators in the given non-empty seq, with
      ///equal probability.
      static member GeneratorIn (generators : seq<Gen<_>>) = 
          generators |> Any.OneOfSeqGen
  
      ///Build a generator that generates a value from one of the generators in the given non-empty seq, with
      ///equal probability.
      static member GeneratorIn ([<ParamArrayAttribute>]  generators : array<Gen<_>>) = 
          generators |> Any.OneOfSeqGen
  
      ///Build a generator that generates a value from one of the generators in the given non-empty seq, with
      ///given probabilities. The sum of the probabilities must be larger than zero.
  
negative.code: 
      ///Build a generator that randomly generates one of the values in the given non-empty seq.
      static member ValueIn (values : seq<_>) = 
          values |> elements
  
      ///Build a generator that randomly generates one of the values in the given non-empty seq.
      static member ValueIn ([<ParamArrayAttribute>] values : array<_>) = 
          values |> elements
  
      ///Generates an integer between l and h, inclusive.
      static member IntBetween (l,h) = 
  