--- a/sat/plugins/plugin_xep_0334.py	Wed Jun 27 07:51:29 2018 +0200
+++ b/sat/plugins/plugin_xep_0334.py	Wed Jun 27 20:14:46 2018 +0200
@@ -20,12 +20,14 @@
 
 from sat.core.i18n import _, D_
 from sat.core.log import getLogger
+
 log = getLogger(__name__)
 from sat.core.constants import Const as C
 
 from sat.tools.common import data_format
 
 from wokkel import disco, iwokkel
+
 try:
     from twisted.words.protocols.xmlstream import XMPPHandler
 except ImportError:
@@ -42,21 +44,24 @@
     C.PI_MAIN: "XEP_0334",
     C.PI_HANDLER: u"yes",
     C.PI_DESCRIPTION: D_(u"""Implementation of Message Processing Hints"""),
-    C.PI_USAGE: dedent(D_(u"""\
+    C.PI_USAGE: dedent(
+        D_(
+            u"""\
              Frontends can use HINT_* constants in mess_data['extra'] in a serialized 'hints' dict.
              Internal plugins can use directly addHint([HINT_* constant]).
-             Will set mess_data['extra']['history'] to 'skipped' when no store is requested and message is not saved in history."""))
-
+             Will set mess_data['extra']['history'] to 'skipped' when no store is requested and message is not saved in history."""
+        )
+    ),
 }
 
-NS_HINTS = u'urn:xmpp:hints'
+NS_HINTS = u"urn:xmpp:hints"
 
 
 class XEP_0334(object):
-    HINT_NO_PERMANENT_STORE = u'no-permanent-store'
-    HINT_NO_STORE = u'no-store'
-    HINT_NO_COPY = u'no-copy'
-    HINT_STORE = u'store'
+    HINT_NO_PERMANENT_STORE = u"no-permanent-store"
+    HINT_NO_STORE = u"no-store"
+    HINT_NO_COPY = u"no-copy"
+    HINT_STORE = u"store"
     HINTS = (HINT_NO_PERMANENT_STORE, HINT_NO_STORE, HINT_NO_COPY, HINT_STORE)
 
     def __init__(self, host):
@@ -69,38 +74,45 @@
         return XEP_0334_handler()
 
     def addHint(self, mess_data, hint):
-        if hint == self.HINT_NO_COPY and not mess_data['to'].resource:
-            log.error(u"{hint} can only be used with full jids! Ignoring it.".format(hint=hint))
+        if hint == self.HINT_NO_COPY and not mess_data["to"].resource:
+            log.error(
+                u"{hint} can only be used with full jids! Ignoring it.".format(hint=hint)
+            )
             return
-        hints = mess_data.setdefault('hints', set())
+        hints = mess_data.setdefault("hints", set())
         if hint in self.HINTS:
             hints.add(hint)
         else:
             log.error(u"Unknown hint: {}".format(hint))
 
     def _sendPostXmlTreatment(self, mess_data):
-        if 'hints' in mess_data:
-            for hint in mess_data['hints']:
-                mess_data[u'xml'].addElement((NS_HINTS, hint))
+        if "hints" in mess_data:
+            for hint in mess_data["hints"]:
+                mess_data[u"xml"].addElement((NS_HINTS, hint))
         return mess_data
 
-    def sendMessageTrigger(self, client, mess_data, pre_xml_treatments, post_xml_treatments):
+    def sendMessageTrigger(
+        self, client, mess_data, pre_xml_treatments, post_xml_treatments
+    ):
         """Add the hints element to the message to be sent"""
-        if u'hints' in mess_data[u'extra']:
-            for hint in data_format.dict2iter(u'hints', mess_data[u'extra'], pop=True):
+        if u"hints" in mess_data[u"extra"]:
+            for hint in data_format.dict2iter(u"hints", mess_data[u"extra"], pop=True):
                 self.addHint(hint)
 
         post_xml_treatments.addCallback(self._sendPostXmlTreatment)
         return True
 
     def _receivedSkipHistory(self, mess_data):
-        mess_data[u'history'] = C.HISTORY_SKIP
+        mess_data[u"history"] = C.HISTORY_SKIP
         return mess_data
 
     def messageReceivedTrigger(self, client, message_elt, post_treat):
         """Check for hints in the received message"""
         for elt in message_elt.elements():
-            if elt.uri == NS_HINTS and elt.name in (self.HINT_NO_PERMANENT_STORE, self.HINT_NO_STORE):
+            if elt.uri == NS_HINTS and elt.name in (
+                self.HINT_NO_PERMANENT_STORE,
+                self.HINT_NO_STORE,
+            ):
                 log.debug(u"history will be skipped for this message, as requested")
                 post_treat.addCallback(self._receivedSkipHistory)
                 break
@@ -110,8 +122,8 @@
 class XEP_0334_handler(XMPPHandler):
     implements(iwokkel.IDisco)
 
-    def getDiscoInfo(self, requestor, target, nodeIdentifier=''):
+    def getDiscoInfo(self, requestor, target, nodeIdentifier=""):
         return [disco.DiscoFeature(NS_HINTS)]
 
-    def getDiscoItems(self, requestor, target, nodeIdentifier=''):
+    def getDiscoItems(self, requestor, target, nodeIdentifier=""):
         return []