--- a/sat/plugins/plugin_xep_0095.py	Wed Jun 27 07:51:29 2018 +0200
+++ b/sat/plugins/plugin_xep_0095.py	Wed Jun 27 20:14:46 2018 +0200
@@ -20,6 +20,7 @@
 from sat.core.i18n import _
 from sat.core.constants import Const as C
 from sat.core.log import getLogger
+
 log = getLogger(__name__)
 from sat.core import exceptions
 from twisted.words.protocols.jabber import xmlstream
@@ -37,19 +38,18 @@
     C.PI_PROTOCOLS: ["XEP-0095"],
     C.PI_MAIN: "XEP_0095",
     C.PI_HANDLER: "yes",
-    C.PI_DESCRIPTION: _("""Implementation of Stream Initiation""")
+    C.PI_DESCRIPTION: _("""Implementation of Stream Initiation"""),
 }
 
 
 IQ_SET = '/iq[@type="set"]'
-NS_SI = 'http://jabber.org/protocol/si'
+NS_SI = "http://jabber.org/protocol/si"
 SI_REQUEST = IQ_SET + '/si[@xmlns="' + NS_SI + '"]'
 SI_PROFILE_HEADER = "http://jabber.org/protocol/si/profile/"
-SI_ERROR_CONDITIONS = ('bad-profile', 'no-valid-streams')
+SI_ERROR_CONDITIONS = ("bad-profile", "no-valid-streams")
 
 
 class XEP_0095(object):
-
     def __init__(self, host):
         log.info(_("Plugin XEP_0095 initialization"))
         self.host = host
@@ -70,7 +70,11 @@
         try:
             del self.si_profiles[si_profile]
         except KeyError:
-            log.error(u"Trying to unregister SI profile [{}] which was not registered".format(si_profile))
+            log.error(
+                u"Trying to unregister SI profile [{}] which was not registered".format(
+                    si_profile
+                )
+            )
 
     def streamInit(self, iq_elt, client):
         """This method is called on stream initiation (XEP-0095 #3.2)
@@ -79,17 +83,21 @@
         """
         log.info(_("XEP-0095 Stream initiation"))
         iq_elt.handled = True
-        si_elt = iq_elt.elements(NS_SI, 'si').next()
-        si_id = si_elt['id']
-        si_mime_type = iq_elt.getAttribute('mime-type', 'application/octet-stream')
-        si_profile = si_elt['profile']
-        si_profile_key = si_profile[len(SI_PROFILE_HEADER):] if si_profile.startswith(SI_PROFILE_HEADER) else si_profile
+        si_elt = iq_elt.elements(NS_SI, "si").next()
+        si_id = si_elt["id"]
+        si_mime_type = iq_elt.getAttribute("mime-type", "application/octet-stream")
+        si_profile = si_elt["profile"]
+        si_profile_key = (
+            si_profile[len(SI_PROFILE_HEADER) :]
+            if si_profile.startswith(SI_PROFILE_HEADER)
+            else si_profile
+        )
         if si_profile_key in self.si_profiles:
-            #We know this SI profile, we call the callback
+            # We know this SI profile, we call the callback
             self.si_profiles[si_profile_key](client, iq_elt, si_id, si_mime_type, si_elt)
         else:
-            #We don't know this profile, we send an error
-            self.sendError(client, iq_elt, 'bad-profile')
+            # We don't know this profile, we send an error
+            self.sendError(client, iq_elt, "bad-profile")
 
     def sendError(self, client, request, condition):
         """Send IQ error as a result
@@ -99,7 +107,7 @@
         """
         if condition in SI_ERROR_CONDITIONS:
             si_condition = condition
-            condition = 'bad-request'
+            condition = "bad-request"
         else:
             si_condition = None
 
@@ -119,8 +127,8 @@
         log.info(_("sending stream initiation accept answer"))
         if misc_elts is None:
             misc_elts = []
-        result_elt = xmlstream.toResponse(iq_elt, 'result')
-        si_elt = result_elt.addElement((NS_SI, 'si'))
+        result_elt = xmlstream.toResponse(iq_elt, "result")
+        si_elt = result_elt.addElement((NS_SI, "si"))
         si_elt.addChild(feature_elt)
         for elt in misc_elts:
             si_elt.addChild(elt)
@@ -134,8 +142,15 @@
             raise exceptions.DataError
         return (iq_elt, si_elt)
 
-
-    def proposeStream(self, client, to_jid, si_profile, feature_elt, misc_elts, mime_type='application/octet-stream'):
+    def proposeStream(
+        self,
+        client,
+        to_jid,
+        si_profile,
+        feature_elt,
+        misc_elts,
+        mime_type="application/octet-stream",
+    ):
         """Propose a stream initiation
 
         @param to_jid(jid.JID): recipient
@@ -154,8 +169,8 @@
 
         offer["from"] = client.jid.full()
         offer["to"] = to_jid.full()
-        si = offer.addElement('si', NS_SI)
-        si['id'] = sid
+        si = offer.addElement("si", NS_SI)
+        si["id"] = sid
         si["mime-type"] = mime_type
         si["profile"] = si_profile
         for elt in misc_elts:
@@ -175,10 +190,17 @@
         self.host = plugin_parent.host
 
     def connectionInitialized(self):
-        self.xmlstream.addObserver(SI_REQUEST, self.plugin_parent.streamInit, client=self.parent)
+        self.xmlstream.addObserver(
+            SI_REQUEST, self.plugin_parent.streamInit, client=self.parent
+        )
 
-    def getDiscoInfo(self, requestor, target, nodeIdentifier=''):
-        return [disco.DiscoFeature(NS_SI)] + [disco.DiscoFeature(u"http://jabber.org/protocol/si/profile/{}".format(profile_name)) for profile_name in self.plugin_parent.si_profiles]
+    def getDiscoInfo(self, requestor, target, nodeIdentifier=""):
+        return [disco.DiscoFeature(NS_SI)] + [
+            disco.DiscoFeature(
+                u"http://jabber.org/protocol/si/profile/{}".format(profile_name)
+            )
+            for profile_name in self.plugin_parent.si_profiles
+        ]
 
-    def getDiscoItems(self, requestor, target, nodeIdentifier=''):
+    def getDiscoItems(self, requestor, target, nodeIdentifier=""):
         return []