--- a/libervia/backend/plugins/plugin_xep_0380.py	Tue Jun 18 12:06:45 2024 +0200
+++ b/libervia/backend/plugins/plugin_xep_0380.py	Wed Jun 19 18:44:57 2024 +0200
@@ -52,32 +52,33 @@
         host.register_namespace("eme", NS_EME)
 
     def _add_eme_element(self, mess_data, namespace, name):
-        message_elt = mess_data['xml']
-        encryption_elt = message_elt.addElement((NS_EME, 'encryption'))
-        encryption_elt['namespace'] = namespace
+        message_elt = mess_data["xml"]
+        encryption_elt = message_elt.addElement((NS_EME, "encryption"))
+        encryption_elt["namespace"] = namespace
         if name is not None:
-            encryption_elt['name'] = name
+            encryption_elt["name"] = name
         return mess_data
 
     def _send_message_trigger(self, client, mess_data, __, post_xml_treatments):
         encryption = mess_data.get(C.MESS_KEY_ENCRYPTION)
         if encryption is not None:
-            namespace = encryption['plugin'].namespace
+            namespace = encryption["plugin"].namespace
             if namespace not in KNOWN_NAMESPACES:
-                name = encryption['plugin'].name
+                name = encryption["plugin"].name
             else:
                 name = None
             post_xml_treatments.addCallback(
-                self._add_eme_element, namespace=namespace, name=name)
+                self._add_eme_element, namespace=namespace, name=name
+            )
         return True
 
     def _message_received_trigger(self, client, message_elt, post_treat):
         try:
-            encryption_elt = next(message_elt.elements(NS_EME, 'encryption'))
+            encryption_elt = next(message_elt.elements(NS_EME, "encryption"))
         except StopIteration:
             return True
 
-        namespace = encryption_elt['namespace']
+        namespace = encryption_elt["namespace"]
         if namespace in client.encryption.get_namespaces():
             # message is encrypted and we can decrypt it
             return True
@@ -86,16 +87,20 @@
 
         # at this point, message is encrypted but we know that we can't decrypt it,
         # we need to notify the user
-        sender_s = message_elt['from']
-        to_jid = jid.JID(message_elt['from'])
+        sender_s = message_elt["from"]
+        to_jid = jid.JID(message_elt["from"])
         algorithm = "{} [{}]".format(name, namespace) if name else namespace
         log.warning(
-            _("Message from {sender} is encrypted with {algorithm} and we can't "
-              "decrypt it.".format(sender=message_elt['from'], algorithm=algorithm)))
+            _(
+                "Message from {sender} is encrypted with {algorithm} and we can't "
+                "decrypt it.".format(sender=message_elt["from"], algorithm=algorithm)
+            )
+        )
 
         user_msg = D_(
             "User {sender} sent you an encrypted message (encrypted with {algorithm}), "
-            "and we can't decrypt it.").format(sender=sender_s, algorithm=algorithm)
+            "and we can't decrypt it."
+        ).format(sender=sender_s, algorithm=algorithm)
 
         extra = {C.MESS_EXTRA_INFO: C.EXTRA_INFO_DECR_ERR}
         client.feedback(to_jid, user_msg, extra)