anchor.diff:          | Some h -> h
           | _      -> raise (IncompatibleMerge "Can not merge two heaps with diferent comparison methods")
   
  -    member this.TryHead () =
  +    member __.TryHead () =
           if count = 0
               then None
               else Some (SBHTreeRoot.findMinRootItem descending roots)
  
positive.code: 
      new(descending) = SkewBinomialHeap(0, descending, [])
  
      member private this.Roots = roots
          
      member this.Count = count
  
      member this.IsDescending = descending
  
      member this.IsEmpty = count = 0
  
      member this.Insert value =
          SkewBinomialHeap (count + 1, descending, SBHTreeRoot.insert descending value roots)
  
      member this.TryMerge (other: 'T SkewBinomialHeap) =
          if descending = other.IsDescending 
              then Some (SkewBinomialHeap (count + other.Count, descending, SBHTreeRoot.mergeRoots descending (SBHTreeRoot.normalize descending roots) (SBHTreeRoot.normalize descending other.Roots)))
              else None
  
negative.code:         | Some t -> t
          | None   -> invalidOp "Empty heap, no head and no tail"
  
      member __.ToList () =
          SBHTreeRoot.toListOrdered descending roots
  
      interface 'T SkewBinomialHeap System.IEquatable with
  