  
          if isinstance(principal, davxml.HRef):
              yield principal
-@@ -1517,6 +1608,270 @@
+@@ -1517,6 +1613,270 @@
          return None
  
      ##

         (dav_namespace, "alternate-URI-set"),
         (dav_namespace, "principal-URL"    ),
         (dav_namespace, "group-member-set" ),
@@ -1585,14 +1940,11 @@
     )
 
     def davComplianceClasses(self):

     """
     Resource representing a WebDAV principal.  (RFC 3744, section 2)
     """
@@ -1577,7 +1937,7 @@
     # WebDAV
     ##
 
