--- a/sat/plugins/plugin_xep_0313.py	Wed Jun 27 07:51:29 2018 +0200
+++ b/sat/plugins/plugin_xep_0313.py	Wed Jun 27 20:14:46 2018 +0200
@@ -21,6 +21,7 @@
 from sat.core.constants import Const as C
 from sat.core.i18n import _
 from sat.core.log import getLogger
+
 log = getLogger(__name__)
 from sat.core import exceptions
 
@@ -45,12 +46,11 @@
     C.PI_PROTOCOLS: ["XEP-0313"],
     C.PI_MAIN: "XEP_0313",
     C.PI_HANDLER: "yes",
-    C.PI_DESCRIPTION: _("""Implementation of Message Archive Management""")
+    C.PI_DESCRIPTION: _("""Implementation of Message Archive Management"""),
 }
 
 
 class XEP_0313(object):
-
     def __init__(self, host):
         log.info(_("Message Archive Management plugin initialization"))
         self.host = host
@@ -86,7 +86,7 @@
     def _queryFinished(self, iq_result, client, elt_list, event):
         client.xmlstream.removeObserver(event, self._appendMessage)
         try:
-            fin_elt = iq_result.elements(mam.NS_MAM, 'fin').next()
+            fin_elt = iq_result.elements(mam.NS_MAM, "fin").next()
         except StopIteration:
             raise exceptions.DataError(u"Invalid MAM result")
 
@@ -119,14 +119,21 @@
         # http://xmpp.org/extensions/xep-0313.html#prefs
         return client._mam.queryPrefs(service)
 
-    def _setPrefs(self, service_s=None, default='roster', always=None, never=None, profile_key=C.PROF_KEY_NONE):
+    def _setPrefs(
+        self,
+        service_s=None,
+        default="roster",
+        always=None,
+        never=None,
+        profile_key=C.PROF_KEY_NONE,
+    ):
         service = jid.JID(service_s) if service_s else None
         always_jid = [jid.JID(entity) for entity in always]
         never_jid = [jid.JID(entity) for entity in never]
-        #TODO: why not build here a MAMPrefs object instead of passing the args separately?
+        # TODO: why not build here a MAMPrefs object instead of passing the args separately?
         return self.setPrefs(service, default, always_jid, never_jid, profile_key)
 
-    def setPrefs(self, client, service=None, default='roster', always=None, never=None):
+    def setPrefs(self, client, service=None, default="roster", always=None, never=None):
         """Set news user preferences.
 
         @param service: entity offering the MAM service (None for user archives)
@@ -143,8 +150,8 @@
 class SatMAMClient(mam.MAMClient):
     implements(disco.IDisco)
 
-    def getDiscoInfo(self, requestor, target, nodeIdentifier=''):
+    def getDiscoInfo(self, requestor, target, nodeIdentifier=""):
         return [disco.DiscoFeature(mam.NS_MAM)]
 
-    def getDiscoItems(self, requestor, target, nodeIdentifier=''):
+    def getDiscoItems(self, requestor, target, nodeIdentifier=""):
         return []