anchor.diff:          | (Br (p, m, s0, s1) as s), Lf (k, x) ->
               if matchPrefix (k, p, m) then
                   if zeroBit (k, m) then
  -                    let left = PatriciaMap.InsertOverwrite (k, x, s0)
  +                    let left = PatriciaMap.Add (k, x, s0)
                       Br (p, m, left, s1)
                   else
  -                    let right = PatriciaMap.InsertOverwrite (k, x, s1)
  +                    let right = PatriciaMap.Add (k, x, s1)
                       Br (p, m, s0, right)
               else
                   PatriciaMap.Join (k, Lf (k, x), p, s)
  
positive.code: 
          (Empty, source)
          ||> Map.fold (fun trie key value ->
              PatriciaMap.Insert (uint32 key, value, trie))
  
      //
      member this.Iterate (action : int -> 'T -> unit) : unit =
  
negative.code: 
          (Empty, source)
          ||> Array.fold (fun trie (key, value) ->
              PatriciaMap.Add (uint32 key, value, trie))
  
      //
      static member OfMap (source : Map<int, 'T>) : PatriciaMap<'T> =
  