anchor.diff:      let inline remove (key : 'k) (map : hmap<'k, 'v>) =
           map.Remove(key)
   
  -    // O(min(n,W))
  +    // O(min(n,32))
       let inline alter (key : 'k) (mapping : Option<'v> -> Option<'v>) (map : hmap<'k, 'v>) =
           map.Alter(key, mapping)
           
  -    // O(min(n,W))
  +    // O(min(n,32))
       let inline update (key : 'k) (mapping : Option<'v> -> 'v) (map : hmap<'k, 'v>) =
           map.Update(key, mapping)
   
  
positive.code:         l.Choose2(r, mapping)
  
  
      // O(min(n,W))
      let inline tryFind (key : 'k) (map : hmap<'k, 'v>) =
          map.TryFind key
          
      // O(min(n,W))
      let inline find (key : 'k) (map : hmap<'k, 'v>) =
          map.Find key
  
      // O(1)
      let inline count (map : hmap<'k, 'v>) = map.Count
  
      // O(1)
      let inline isEmpty (map : hmap<'k, 'v>) = map.IsEmpty
  
  
negative.code:     let inline union (l : hmap<'k, 'v>) (r : hmap<'k, 'v>) =
          l.Union r
  
      // O(min(n,32))
      let inline tryRemove (key : 'k) (map : hmap<'k, 'v>) =
          map.TryRemove key
  
  