anchor.diff:     (test-function
       :type function
       :initarg :function
  -    :accessor test-function
  -    :type function)
  +    :accessor test-function)
      )
     (:documentation
   "A predicate is defined for application in a predicate test session,
  
positive.code:     ;; on a sidebar, with this slot definition interpreted as a
      ;; predicate, this may resemble the RDF:LABEL property
      :initarg :label
      :type (or string null)
      :initform nil
      :accessor labeled-object-label)))
  
  
negative.code:     (cond
        (nmp
         ;; FIXME: The semantics of predicates and results-tests
         ;; may need description
         (let* ((result-values (multiple-value-list (call-next-method)))
                (expect-values (test-expect-values test))
                (result-okidoke-p
  