anchor.diff:              Some write
           | None -> None
   
  +/// Various helper functions for XML attribute
  +/// serialization
   module internal AttributeSerializer =
   
       open System
  
positive.code:     and determineWriterInfo (ps, attrs) (pi : PropertyInfo) =
          match getAttribute<XmlAttributeAttribute> pi with
          | Some attr ->
              let key = if notWhite attr.Name then attr.Name else pi.Name
              let getter = ReflectionHelpers.getObjGetter pi
              let info = { GetFunc = getter; Key = key; WriteFunc = lazy getWriterFunc pi.PropertyType }
              ps, info :: attrs 
          | None ->
              let info = buildPropertyWriterInfo pi
  
negative.code:     open Extensions
      open Utils
  
      let nullableStrFunc<'a when 'a: (new: unit -> 'a)
                              and 'a :> ValueType
                              and 'a: struct> (func : 'a -> string) =
          SerializerFunc(fun (v : obj) ->
              let value : Nullable<'a> = unbox v
              if value.HasValue then func value.Value else null)
  
      let writeGuid (v : Guid) =
          v.ToString("N")
  