make subcomments_count usable as a function taking any commentable object as argument

entities.py

@@ -14,6 +14,11 @@
 from cubicweb.selectors import implements
 from cubicweb.entities import AnyEntity, fetch_config
 
+
+def subcomments_count(commentable):
+    return sum([len(commentable.reverse_comments)]
+               + [subcomments_count(c) for c in commentable.reverse_comments])
+
 class Comment(TreeMixIn, AnyEntity):
     """customized class for Comment entities"""
     __regid__ = 'Comment'
@@ -34,10 +39,9 @@
         """
         return self.root().rest_path(), {}
 
-    def subcomments_count(self):
-        return sum([len(self.reverse_comments)]
-                   + [c.subcomments_count() for c in self.reverse_comments])
+    subcomments_count = subcomments_count
+
 
 # some views potentially needed on web *and* server side (for notification)
 # so put them here
 
@@ -40,8 +44,7 @@
 
 # some views potentially needed on web *and* server side (for notification)
 # so put them here
 
-
 class CommentFullTextView(EntityView):
     __regid__ = 'fulltext'
     __select__ = implements('Comment')