anchor.diff:     and
        is-instance? ((BasicPerson.new) "w" 2) BasicPerson
        equal? 2
  -       ((BasicPerson.new) "w" 2).age
  +       (BasicPerson (.new "w" 2)) .age
   #
   #  A class which uses the .new in Object, and adds type checking
   #
   class PersonTraditional (Object)
  -
      def .init((name=String) (age = Bignum))
         define .name name
         define .age age
   
   
   class PersonModern ()
  -
      def .valid?(obj)
  -      is? (obj.name) String
  -      is? (obj.age) Bignum
  -
  +      is? obj!name String
  +      is? obj!age Bignum
      def .new(name age)
         (dict)                             # create the object
            define .name name               # add the data
  
positive.code: #  A class which does it's own construction but checks nothing
  #
  class BasicPerson ()
  
      def .new (name age)
        (tag .self (dict))
          define .name name
  
negative.code: assert
     and
       is-instance? fred PersonModern
       equal? fred!age 23
  