diff --git a/mylib/ldap.py b/mylib/ldap.py
index 4ee1757..056b5df 100644
--- a/mylib/ldap.py
+++ b/mylib/ldap.py
@@ -228,6 +228,7 @@ class LdapServer:
     def format_changes(old, new, ignore_attrs=None, prefix=None):
         """ Format changes (modlist) on an object based on its old and new attributes values to display/log it """
         msg = []
+        prefix = prefix if prefix else ''
         for (op, attr, val) in modlist.modifyModlist(old, new, ignore_attr_types=ignore_attrs if ignore_attrs else []):
             if op == ldap.MOD_ADD:  # pylint: disable=no-member
                 op = 'ADD'
@@ -238,7 +239,7 @@ class LdapServer:
             else:
                 op = 'UNKNOWN (=%s)' % op
             if val is None and op == 'DELETE':
-                msg.append('%s - %s %s' % (prefix if prefix else '', op, attr))
+                msg.append('%s - %s %s' % (prefix, op, attr))
             else:
                 msg.append('%s - %s %s: %s' % (prefix, op, attr, val))
         return '\n'.join(msg)
@@ -502,6 +503,12 @@ class LdapClient:
             return None
         return (old, new)
 
+    def format_changes(self, changes, protected_attrs=None, prefix=None):
+        return self.cnx.format_changes(
+            changes[0], changes[1],
+            ignore_attrs=protected_attrs, prefix=prefix
+        )
+
     def add_object(self, dn, attrs):
         """
         Add an object