anchor.diff:                  I.DOMImplementationList
                   I.DOMLocator
                   I.DOMStringList
  +                I.DOMRect
                   I.Document
                   I.DocumentFragment
                   I.DocumentType
  
positive.code:         |+> Instance [
                  "schemaTypeInfo" =@ TypeInfo
                  "tagName" =@ T<string>
                  "getAttribute" => T<string->string>
                  "setAttribute" => T<string> * T<string> ^-> T<unit>
                  "removeAttribute" => T<string->unit>
  
negative.code:                     T<string> ^-> DOMImplementation
                  "getDOMImplementationList" =>
                      T<string> ^-> DOMImplementationList
              ]
  
      let DOMRect =
          Class "DomRect"
          |+> Instance [
                  "x" =? T<double>
                  "y" =? T<double>
                  "width" =? T<double>
                  "height" =? T<double>
                  "top" =? T<double>
                  "right" =? T<double>
                  "bottom" =? T<double>
                  "left" =? T<double>
              ]
  
      let EventTarget =
  