anchor.diff:      let set = Set.remove minElement set
       minElement, set
   
  -//
  +/// Extracts the maximum element from a set, returning the element
  +/// along with the updated set.
   [<CompiledName("ExtractMaximum")>]
  -let extractMax (set : Set<'T>) =
  +let extractMax (set : Set<'T>) : 'T * Set<'T> =
       // Preconditions
       checkNonNull "set" set
       if Set.isEmpty set then
  
positive.code:     | Some result ->
          result
      | None ->
          raise <| System.Collections.Generic.KeyNotFoundException ()
  
  //
  
negative.code: 
  //
  [<CompiledName("FoldIndexed")>]
  let foldi (folder : 'State -> int -> 'T -> 'State) (state : 'State) (set : Set<'T>) : 'State =
      // Preconditions
      checkNonNull "set" set
  
  