--- a/MCClassComment.st	Mon May 25 13:24:22 2020 +0100
+++ b/MCClassComment.st	Mon May 25 13:25:27 2020 +0100
@@ -1,5 +1,7 @@
 "{ Package: 'stx:goodies/monticello' }"
 
+"{ NameSpace: Smalltalk }"
+
 MCDefinition subclass:#MCClassComment
 	instanceVariableNames:'className comment source'
 	classVariableNames:''
@@ -29,13 +31,25 @@
 !
 
 sortKey
-    self halt:'please define sortKey here'.
+    ^ self summary
+
+    "Modified: / 25-05-2020 / 12:42:13 / Jan Vrany <jan.vrany@fit.cvut.cz>"
 !
 
 source
     ^ source
 ! !
 
+!MCClassComment methodsFor:'comparing'!
+
+description
+    "superclass MCDefinition says that I am responsible to implement this method"
+
+    ^ Array with: self summary
+
+    "Modified: / 25-05-2020 / 12:34:33 / Jan Vrany <jan.vrany@fit.cvut.cz>"
+! !
+
 !MCClassComment methodsFor:'converting'!
 
 asChange
@@ -51,6 +65,26 @@
     actualClass comment:comment
 ! !
 
+!MCClassComment methodsFor:'printing'!
+
+summary
+    "superclass MCDefinition says that I am responsible to implement this method"
+
+    ^ className , ' (comment)'
+
+    "Modified: / 25-05-2020 / 12:34:46 / Jan Vrany <jan.vrany@fit.cvut.cz>"
+! !
+
+!MCClassComment methodsFor:'visiting'!
+
+accept:aVisitor
+    "raise an error: must be redefined in concrete subclass(es)"
+
+    ^ aVisitor visitClassComment: self.
+
+    "Created: / 25-05-2020 / 12:38:14 / Jan Vrany <jan.vrany@fit.cvut.cz>"
+! !
+
 !MCClassComment class methodsFor:'documentation'!
 
 version