diff --git a/modoboa/extensions/stats/graphics.py b/modoboa/extensions/stats/graphics.py
index d7f657ba9..80ca0af88 100644
--- a/modoboa/extensions/stats/graphics.py
+++ b/modoboa/extensions/stats/graphics.py
@@ -7,10 +7,12 @@ from modoboa.lib.sysutils import exec_cmd
 
 
 class Curve(object):
+
     """Graphic curve.
 
     Simple way to represent a graphic curve.
     """
+
     def __init__(self, dsname, color, legend, cfunc="AVERAGE"):
         """Constructor.
         """
@@ -37,9 +39,11 @@ class Curve(object):
 
 
 class Graphic(object):
+
     """Graphic.
 
     """
+
     def __init__(self):
         """Constructor.
         """
@@ -76,7 +80,7 @@ class Graphic(object):
             cmdargs += curve.to_rrd_command_args(rrdfile)
         cmd = "rrdtool xport --start %s --end %s " % (str(start), str(end))
         cmd += " ".join(cmdargs)
-        if type(cmd) is unicode:
+        if isinstance(cmd, unicode):
             cmd = cmd.encode("utf-8")
         code, output = exec_cmd(cmd)
         if code:
@@ -95,6 +99,7 @@ class Graphic(object):
 
 
 class AverageTraffic(Graphic):
+
     """Average traffic.
     """
     title = ugettext_lazy('Average traffic (msgs/min)')
@@ -109,6 +114,7 @@ class AverageTraffic(Graphic):
 
 
 class AverageTrafficSize(Graphic):
+
     """Average traffic size.
     """
     title = ugettext_lazy('Average normal traffic size (bytes/min)')
diff --git a/modoboa/extensions/stats/lib.py b/modoboa/extensions/stats/lib.py
index c71e5b59d..9d78c039f 100644
--- a/modoboa/extensions/stats/lib.py
+++ b/modoboa/extensions/stats/lib.py
@@ -12,7 +12,7 @@ def date_to_timestamp(timetuple):
     :return: an integer
     """
     date = " ".join(
-        [("%d" % elem) if type(elem) is int else elem for elem in timetuple]
+        [("%d" % elem) if isinstance(elem, int) else elem for elem in timetuple]
     )
     fmt = "%Y %m %d %H %M %S" \
           if timetuple[1].isdigit() else "%Y %b %d %H %M %S"
diff --git a/modoboa/extensions/stats/management/commands/logparser.py b/modoboa/extensions/stats/management/commands/logparser.py
index c622c5e05..3613f056b 100644
--- a/modoboa/extensions/stats/management/commands/logparser.py
+++ b/modoboa/extensions/stats/management/commands/logparser.py
@@ -21,10 +21,11 @@ import time
 import sys
 import os
 import re
-import rrdtool
 import string
 from optparse import make_option
 
+import rrdtool
+
 from django.core.management.base import BaseCommand
 
 from modoboa.core.extensions import exts_pool
@@ -71,9 +72,11 @@ class LogParser(object):
         self.workdict = {}
         self.lupdates = {}
         self._s_date_expr = \
-            re.compile(r"(?P<month>\w+)\s+(?P<day>\d+)\s+(?P<hour>\d+):(?P<min>\d+):(?P<sec>\d+)(?P<eol>.*)")
+            re.compile(
+                r"(?P<month>\w+)\s+(?P<day>\d+)\s+(?P<hour>\d+):(?P<min>\d+):(?P<sec>\d+)(?P<eol>.*)")
         self._hp_date_expr = \
-            re.compile(r"(?P<year>\d+)-(?P<month>\d+)-(?P<day>\d+)T(?P<hour>\d+):(?P<min>\d+):(?P<sec>\d+)\.\d+\+\d+:\d+(?P<eol>.*)")
+            re.compile(
+                r"(?P<year>\d+)-(?P<month>\d+)-(?P<day>\d+)T(?P<hour>\d+):(?P<min>\d+):(?P<sec>\d+)\.\d+\+\d+:\d+(?P<eol>.*)")
         self.date_expr = None
         self.line_expr = \
             re.compile(r"\s+([-\w]+)\s+(\w+)/?\w*[[](\d+)[]]:\s+(.*)")
@@ -200,7 +203,7 @@ class LogParser(object):
             self.lupdates[fname] = self.init_rrd(fname, m)
             self._dprint("[rrd] create new RRD file %s" % fname)
         else:
-            if not fname in self.lupdates:
+            if fname not in self.lupdates:
                 self.lupdates[fname] = rrdtool.last(str(fname))
 
         if m <= self.lupdates[fname]:
@@ -250,11 +253,11 @@ class LogParser(object):
 
     def inc_counter(self, dom, counter, val=1):
         if dom is not None and dom in self.domains:
-            if not self.cur_t in self.data[dom]:
+            if self.cur_t not in self.data[dom]:
                 self.initcounters(dom)
             self.data[dom][self.cur_t][counter] += val
 
-        if not self.cur_t in self.data["global"]:
+        if self.cur_t not in self.data["global"]:
             self.initcounters("global")
         self.data["global"][self.cur_t][counter] += val
 
@@ -299,7 +302,9 @@ class LogParser(object):
             return
         (line_id, line_log) = m.groups()
         if line_id == "NOQUEUE":
-            addrto = re.match("reject: .*from=<.*> to=<[^@]+@([^>]+)>", line_log)
+            addrto = re.match(
+                "reject: .*from=<.*> to=<[^@]+@([^>]+)>",
+                line_log)
             if addrto and addrto.group(1) in self.domains:
                 self.inc_counter(addrto.group(1), 'reject')
             return
@@ -316,9 +321,9 @@ class LogParser(object):
 
         m = re.search("to=<([^>]*)>.*status=(\S+)", line_log)
         if m is not None:
-            if not line_id in self.workdict:
-                self._dprint("Inconsistent mail (%s: %s), skipping" \
-                                 % (line_id, m.group(1)))
+            if line_id not in self.workdict:
+                self._dprint("Inconsistent mail (%s: %s), skipping"
+                             % (line_id, m.group(1)))
                 return
             if not m.group(2) in variables:
                 self._dprint("Unsupported status %s, skipping" % m.group(2))
diff --git a/modoboa/extensions/stats/views.py b/modoboa/extensions/stats/views.py
index 49e1570d9..b16756408 100644
--- a/modoboa/extensions/stats/views.py
+++ b/modoboa/extensions/stats/views.py
@@ -1,4 +1,7 @@
 # coding: utf-8
+
+"""Custom views."""
+
 import re
 import time
 from django.shortcuts import render
@@ -83,7 +86,7 @@ def check_domain_access(user, pattern):
 def graphs(request):
     gset = request.GET.get("gset", None)
     gsets = events.raiseDictEvent("GetGraphSets")
-    if not gset in gsets:
+    if gset not in gsets:
         raise NotFound(_("Unknown graphic set"))
     searchq = request.GET.get("searchquery", None)
     period = request.GET.get("period", "day")
@@ -94,7 +97,7 @@ def graphs(request):
     tplvars["domain"] = domain
 
     if period == "custom":
-        if not "start" in request.GET or not "end" in request.GET:
+        if "start" not in request.GET or "end" not in request.GET:
             raise BadRequest(_("Bad custom period"))
         start = request.GET["start"]
         end = request.GET["end"]