diff --git a/plone/__init__.py b/plone/__init__.py
index de40ea7..5284146 100644
--- a/plone/__init__.py
+++ b/plone/__init__.py
@@ -1 +1 @@
-__import__('pkg_resources').declare_namespace(__name__)
+__import__("pkg_resources").declare_namespace(__name__)
diff --git a/plone/event/adapters.py b/plone/event/adapters.py
index 2ce3afc..2549298 100644
--- a/plone/event/adapters.py
+++ b/plone/event/adapters.py
@@ -14,7 +14,7 @@ class EventAccessor:
     """
 
     def __init__(self, context):
-        object.__setattr__(self, 'context', context)
+        object.__setattr__(self, "context", context)
 
     def __getattr__(self, name):
         return getattr(self.context, name)
diff --git a/plone/event/interfaces.py b/plone/event/interfaces.py
index 8dc85bc..5f3af6e 100644
--- a/plone/event/interfaces.py
+++ b/plone/event/interfaces.py
@@ -3,9 +3,7 @@
 
 
 class IEvent(Interface):
-    """Event type marker interface.
-
-    """
+    """Event type marker interface."""
 
 
 class IEventRecurrence(Interface):
@@ -20,8 +18,9 @@ class IOccurrence(Interface):
     occurrence.
 
     """
-    start = Attribute('Occurrence start date')
-    end = Attribute('Occurrence end date')
+
+    start = Attribute("Occurrence start date")
+    end = Attribute("Occurrence end date")
 
 
 class ICalendarAccessor(Interface):
@@ -30,16 +29,15 @@ class ICalendarAccessor(Interface):
     A calendar is a collection of calendar components, like events.
 
     """
-    uid = Attribute('UID of the calendar. Autogenerated, read only.')
+
+    uid = Attribute("UID of the calendar. Autogenerated, read only.")
     # rw attributes
-    title = Attribute('Calendar title.')
-    description = Attribute('Calendar description text.')
-    timezone = Attribute('Default timezone of the calendar.')
+    title = Attribute("Calendar title.")
+    description = Attribute("Calendar description text.")
+    timezone = Attribute("Default timezone of the calendar.")
 
     def items(self):
-        """Return a list of calendar component items, like events.
-
-        """
+        """Return a list of calendar component items, like events."""
 
 
 class IEventAccessor(Interface):
@@ -51,40 +49,38 @@ class IEventAccessor(Interface):
     """
 
     # ro attributes
-    uid = Attribute('UID of the event. Autogenerated, read only.')
-    created = Attribute('Python datetime of the event creation timestamp.')
-    duration = Attribute('Duration of the event. Computed attribute.')
+    uid = Attribute("UID of the event. Autogenerated, read only.")
+    created = Attribute("Python datetime of the event creation timestamp.")
+    duration = Attribute("Duration of the event. Computed attribute.")
 
     # reference
     url = Attribute(
-        'Cannonical, unique url of the event. External events '
-        'are referenced by the origin url unless explicitly set.'
+        "Cannonical, unique url of the event. External events "
+        "are referenced by the origin url unless explicitly set."
     )
 
     # rw attributes
-    last_modified = Attribute('Last modified Python datetime.')
-    title = Attribute('Event title.')
-    description = Attribute('Event description text.')
-    start = Attribute('Event start date as Python datetime.')
-    end = Attribute('Event end date as Python datetime.')
-    whole_day = Attribute('Event lasts whole day.')
-    open_end = Attribute('Event has no defined end time.')
-    timezone = Attribute('Timezone of the event. A pytz timezone identifier.')
-    recurrence = Attribute('RFC5545 compatible recurrence definition.')
-    location = Attribute('Location of the event.')
-    attendees = Attribute('List of attendees.')
-    contact_name = Attribute('Contact name.')
-    contact_email = Attribute('Contact email.')
-    contact_phone = Attribute('Contact phone.')
-    event_url = Attribute('Website of the event.')
-    subjects = Attribute('Categories.')
-    text = Attribute('Body text of the event.')
+    last_modified = Attribute("Last modified Python datetime.")
+    title = Attribute("Event title.")
+    description = Attribute("Event description text.")
+    start = Attribute("Event start date as Python datetime.")
+    end = Attribute("Event end date as Python datetime.")
+    whole_day = Attribute("Event lasts whole day.")
+    open_end = Attribute("Event has no defined end time.")
+    timezone = Attribute("Timezone of the event. A pytz timezone identifier.")
+    recurrence = Attribute("RFC5545 compatible recurrence definition.")
+    location = Attribute("Location of the event.")
+    attendees = Attribute("List of attendees.")
+    contact_name = Attribute("Contact name.")
+    contact_email = Attribute("Contact email.")
+    contact_phone = Attribute("Contact phone.")
+    event_url = Attribute("Website of the event.")
+    subjects = Attribute("Categories.")
+    text = Attribute("Body text of the event.")
 
 
 class IRecurrenceSupport(Interface):
-    """Event type recurrence adatper.
-
-    """
+    """Event type recurrence adatper."""
 
     def occurrences(self, range_start, range_end):
         """Return a list of IOccurrence objects with custom attributes of the
@@ -100,9 +96,7 @@ def occurrences(self, range_start, range_end):
 
 
 class IICalendar(Interface):
-    """Adapter, which is used to construct an icalendar object.
-
-    """
+    """Adapter, which is used to construct an icalendar object."""
 
 
 class IICalendarEventComponent(Interface):
@@ -155,37 +149,38 @@ class / created / description / geo /
     resources / rdate / x-prop / iana-prop
 
     """
-    dtstart = Attribute('Start Date/Time')
-    dtend = Attribute('End Date/Time')
-    duration = Attribute('Duration')
-    rrule = Attribute('Recurrence Rule')
-    description = Attribute('Description')
-    location = Attribute('Location')
-    summary = Attribute('Summary')
-    url = Attribute('Url')
-    attendee = Attribute('Attendee')
-    categories = Attribute('Categories')
-    contact = Attribute('Contact')
-
-    exdate = Attribute('Exdate')
-    rdate = Attribute('Rdate')
-
-    dtstamp = Attribute('Timestamp')
-    uid = Attribute('Unique identifier')
-    klass = Attribute('Class')  # class
-    created = Attribute('Created')
-    geo = Attribute('Geo')
-    last_mod = Attribute('Last Modified')  # last-mod
-    organizer = Attribute('Organizer')
-    priority = Attribute('Priority')
-    seq = Attribute('Seq')
-    status = Attribute('Status')
-    transp = Attribute('Transp')
-    recurid = Attribute('Recurid')
-    attach = Attribute('Attach')
-    comment = Attribute('Comment')
-    rstatus = Attribute('Rstatus')
-    related = Attribute('Related')
-    resources = Attribute('Resources')
-    x_prop = Attribute('X Prop')  # x-prop
-    iana_prop = Attribute('Iana Prop')  # iana-prop
+
+    dtstart = Attribute("Start Date/Time")
+    dtend = Attribute("End Date/Time")
+    duration = Attribute("Duration")
+    rrule = Attribute("Recurrence Rule")
+    description = Attribute("Description")
+    location = Attribute("Location")
+    summary = Attribute("Summary")
+    url = Attribute("Url")
+    attendee = Attribute("Attendee")
+    categories = Attribute("Categories")
+    contact = Attribute("Contact")
+
+    exdate = Attribute("Exdate")
+    rdate = Attribute("Rdate")
+
+    dtstamp = Attribute("Timestamp")
+    uid = Attribute("Unique identifier")
+    klass = Attribute("Class")  # class
+    created = Attribute("Created")
+    geo = Attribute("Geo")
+    last_mod = Attribute("Last Modified")  # last-mod
+    organizer = Attribute("Organizer")
+    priority = Attribute("Priority")
+    seq = Attribute("Seq")
+    status = Attribute("Status")
+    transp = Attribute("Transp")
+    recurid = Attribute("Recurid")
+    attach = Attribute("Attach")
+    comment = Attribute("Comment")
+    rstatus = Attribute("Rstatus")
+    related = Attribute("Related")
+    resources = Attribute("Resources")
+    x_prop = Attribute("X Prop")  # x-prop
+    iana_prop = Attribute("Iana Prop")  # iana-prop
diff --git a/plone/event/recurrence.py b/plone/event/recurrence.py
index 7dd27ea..e2b528b 100644
--- a/plone/event/recurrence.py
+++ b/plone/event/recurrence.py
@@ -15,12 +15,12 @@
 
 
 def recurrence_sequence_ical(
-        start,
-        recrule=None,
-        from_=None,
-        until=None,
-        count=None,
-        duration=None,
+    start,
+    recrule=None,
+    from_=None,
+    until=None,
+    count=None,
+    duration=None,
 ):
     """Calculates a sequence of datetime objects from a recurrence rule
     following the RFC2445 specification, using python-dateutil recurrence
@@ -67,7 +67,7 @@ def recurrence_sequence_ical(
     _from = tzdel(from_)
     _until = tzdel(until)
     if duration:
-        assert (isinstance(duration, datetime.timedelta))
+        assert isinstance(duration, datetime.timedelta)
     else:
         duration = datetime.timedelta(0)
 
@@ -87,16 +87,16 @@ def recurrence_sequence_ical(
         # time for UNTIL, RDATE and EXDATE.
         t0 = start.time()  # set initial time information.
         # First, replace all times in the recurring rule with starttime
-        t0str = f'T{t0.hour:02d}{t0.minute:02d}{t0.second:02d}'
+        t0str = f"T{t0.hour:02d}{t0.minute:02d}{t0.second:02d}"
         # Replace any times set to 000000 with start time, not all
         # rrules are set by a specific broken widget.  Don't waste time
         # subbing if the start time is already 000000.
-        if t0str != 'T000000':
-            recrule = re.sub(r'T000000', t0str, recrule)
+        if t0str != "T000000":
+            recrule = re.sub(r"T000000", t0str, recrule)
         # Then, replace incorrect until times with the end of the day
         recrule = re.sub(
-            r'(UNTIL[^T]*[0-9]{8})T(000000)',
-            r'\1T235959',
+            r"(UNTIL[^T]*[0-9]{8})T(000000)",
+            r"\1T235959",
             recrule,
         )
 
@@ -140,13 +140,13 @@ def recurrence_sequence_ical(
 
 
 def recurrence_sequence_timedelta(
-        start,
-        delta=None,
-        until=None,
-        count=None,
-        dst=DSTAUTO,
+    start,
+    delta=None,
+    until=None,
+    count=None,
+    dst=DSTAUTO,
 ):
-    """ Calculates a sequence of datetime objects from a timedelta integer,
+    """Calculates a sequence of datetime objects from a timedelta integer,
     which defines the minutes between each occurence.
 
     :param start: datetime or DateTime instance of the date from which the
@@ -204,7 +204,7 @@ def recurrence_sequence_timedelta(
 
 
 def recurrence_int_sequence(sequence):
-    """ Generates a sequence of integer representations from a sequence of
+    """Generates a sequence of integer representations from a sequence of
     dateime instances.
 
     :param sequence: An iterable sequence of datetime instances.
diff --git a/plone/event/tests/test_adapters.py b/plone/event/tests/test_adapters.py
index ad51528..df92e79 100644
--- a/plone/event/tests/test_adapters.py
+++ b/plone/event/tests/test_adapters.py
@@ -15,15 +15,17 @@ class MockObject:
 class TestAdapters(unittest.TestCase):
     def setUp(self):
         import zope.component
-        context = xmlconfig.file('meta.zcml', zope.component)
-        xmlconfig.file('configure.zcml', zope.component, context=context)
+
+        context = xmlconfig.file("meta.zcml", zope.component)
+        xmlconfig.file("configure.zcml", zope.component, context=context)
 
         import plone.event
-        xmlconfig.file('configure.zcml', plone.event, context=context)
+
+        xmlconfig.file("configure.zcml", plone.event, context=context)
 
     def test_event_accessor(self):
         obj = MockObject()
-        tz = pytz.timezone('Europe/Vienna')
+        tz = pytz.timezone("Europe/Vienna")
         obj.start = datetime(2012, 12, 12, 10, 0, tzinfo=tz)
         obj.end = datetime(2012, 12, 12, 12, 0, tzinfo=tz)
         zope.interface.alsoProvides(obj, IEvent)
@@ -48,9 +50,9 @@ def test_event_accessor(self):
         acc.something = True
         self.assertTrue(acc.something == obj.something is True)
         del acc.something
-        self.assertTrue(hasattr(acc, 'something') is False)
-        self.assertTrue(hasattr(obj, 'something') is False)
+        self.assertTrue(hasattr(acc, "something") is False)
+        self.assertTrue(hasattr(obj, "something") is False)
 
         del acc.start
-        self.assertTrue(hasattr(acc, 'start') is False)
-        self.assertTrue(hasattr(obj, 'start') is False)
+        self.assertTrue(hasattr(acc, "start") is False)
+        self.assertTrue(hasattr(obj, "start") is False)
diff --git a/plone/event/tests/test_doctest.py b/plone/event/tests/test_doctest.py
index 001e083..6e7b759 100644
--- a/plone/event/tests/test_doctest.py
+++ b/plone/event/tests/test_doctest.py
@@ -7,11 +7,13 @@
 
 OPTIONFLAGS = doctest.NORMALIZE_WHITESPACE | doctest.ELLIPSIS
 DOCFILES = [
-    'recurrence.rst',
-    'recurrence_dateutil.rst',
-    'utils.rst',
+    "recurrence.rst",
+    "recurrence_dateutil.rst",
+    "utils.rst",
+]
+DOCMODS = [
+    "plone.event.utils",
 ]
-DOCMODS = ['plone.event.utils', ]
 
 
 def test_suite():
@@ -19,24 +21,19 @@ def test_suite():
     suite.addTests(
         [
             doctest.DocFileSuite(
-                os.path.join(os.path.dirname(__file__), '..', docfile),
+                os.path.join(os.path.dirname(__file__), "..", docfile),
                 module_relative=False,
                 optionflags=OPTIONFLAGS,
-                tearDown=tearDown
+                tearDown=tearDown,
             )
             for docfile in DOCFILES
         ]
     )
     suite.addTests(
-        [
-            doctest.DocTestSuite(
-                docmod, optionflags=OPTIONFLAGS
-            )
-            for docmod in DOCMODS
-        ]
+        [doctest.DocTestSuite(docmod, optionflags=OPTIONFLAGS) for docmod in DOCMODS]
     )
     return suite
 
 
-if __name__ == '__main__':
-    unittest.main(defaultTest='test_suite')
+if __name__ == "__main__":
+    unittest.main(defaultTest="test_suite")
diff --git a/plone/event/tests/test_recurrence_int_sequence.py b/plone/event/tests/test_recurrence_int_sequence.py
index b858a9c..9812fb4 100644
--- a/plone/event/tests/test_recurrence_int_sequence.py
+++ b/plone/event/tests/test_recurrence_int_sequence.py
@@ -4,10 +4,11 @@
 
 
 class TestRecurrenceIntSequence(unittest.TestCase):
-    @mock.patch('plone.event.recurrence.dt2int')
+    @mock.patch("plone.event.recurrence.dt2int")
     def test_recrule_str_(self, dt2int):
         from plone.event.recurrence import recurrence_int_sequence
+
         sequence = [1, 2, 3]
-        dt2int.return_value = 'a'
+        dt2int.return_value = "a"
         res = [a for a in recurrence_int_sequence(sequence)]
-        self.assertEqual(res, ['a', 'a', 'a'])
+        self.assertEqual(res, ["a", "a", "a"])
diff --git a/plone/event/tests/test_recurrence_sequence_ical.py b/plone/event/tests/test_recurrence_sequence_ical.py
index ae08c8f..25f1887 100644
--- a/plone/event/tests/test_recurrence_sequence_ical.py
+++ b/plone/event/tests/test_recurrence_sequence_ical.py
@@ -5,6 +5,7 @@ class TestRecurrenceSequenceIcal(unittest.TestCase):
     def test_start(self):
         from datetime import datetime
         from plone.event.recurrence import recurrence_sequence_ical
+
         start = datetime(2011, 11, 23)
         seq = recurrence_sequence_ical(start)
         results = [res for res in seq]
@@ -13,18 +14,20 @@ def test_start(self):
     def test_recrule_str(self):
         from datetime import datetime
         from plone.event.recurrence import recurrence_sequence_ical
+
         start = datetime(2011, 11, 23)
-        recrule = 'FREQ=DAILY;INTERVAL=10;COUNT=5'
+        recrule = "FREQ=DAILY;INTERVAL=10;COUNT=5"
         seq = recurrence_sequence_ical(start, recrule=recrule)
         results = [res for res in seq]
         self.assertEqual(len(results), 5)
 
     def test_recrule_str_rdate(self):
         """Test, if an RDATE date has the correct time set.
-            See: "BUGFIX WRONG RDATE TIME" in recurrence.py
+        See: "BUGFIX WRONG RDATE TIME" in recurrence.py
         """
         from datetime import datetime
         from plone.event.recurrence import recurrence_sequence_ical
+
         start = datetime(2011, 11, 23, 10, 10)
         recrule = """FREQ=DAILY;INTERVAL=1;COUNT=3
 RDATE:20111129T000000"""
@@ -34,22 +37,22 @@ def test_recrule_str_rdate(self):
         self.assertEqual(results[0].time(), results[-1].time())
 
     def test_recrule_str_exdate(self):
-        """Test, if an EXDATE date are not in the resulting recurrence set.
-        """
+        """Test, if an EXDATE date are not in the resulting recurrence set."""
         from datetime import datetime
         from plone.event.recurrence import recurrence_sequence_ical
 
         import pytz
-        at = pytz.timezone('Europe/Vienna')
+
+        at = pytz.timezone("Europe/Vienna")
         start = at.localize(datetime(2013, 6, 29, 10, 10))
-        recrule = 'RRULE:FREQ=DAILY;COUNT=4\r\nEXDATE:20130630T000000,20130701T000000\r\nRDATE:20130706T000000,20130809T000000'  # noqa
+        recrule = "RRULE:FREQ=DAILY;COUNT=4\r\nEXDATE:20130630T000000,20130701T000000\r\nRDATE:20130706T000000,20130809T000000"  # noqa
         seq = recurrence_sequence_ical(start, recrule=recrule)
         res = [res for res in seq]
         res_test = [
             at.localize(datetime(2013, 6, 29, 10, 10)),
             at.localize(datetime(2013, 7, 2, 10, 10)),
             at.localize(datetime(2013, 7, 6, 10, 10)),
-            at.localize(datetime(2013, 8, 9, 10, 10))
+            at.localize(datetime(2013, 8, 9, 10, 10)),
         ]
         self.assertEqual(len(res), 4)
         self.assertEqual(res, res_test)
@@ -62,16 +65,17 @@ def test_recrule_str_until(self):
         from plone.event.recurrence import recurrence_sequence_ical
 
         import pytz
-        at = pytz.timezone('Europe/Vienna')
+
+        at = pytz.timezone("Europe/Vienna")
         start = at.localize(datetime(2013, 6, 29, 10, 10))
-        recrule = 'RRULE:FREQ=DAILY;UNTIL=20130702T000000'
+        recrule = "RRULE:FREQ=DAILY;UNTIL=20130702T000000"
         seq = recurrence_sequence_ical(start, recrule=recrule)
         res = [res for res in seq]
         res_test = [
             at.localize(datetime(2013, 6, 29, 10, 10)),
             at.localize(datetime(2013, 6, 30, 10, 10)),
             at.localize(datetime(2013, 7, 1, 10, 10)),
-            at.localize(datetime(2013, 7, 2, 10, 10))
+            at.localize(datetime(2013, 7, 2, 10, 10)),
         ]
         self.assertEqual(len(res), 4)
         self.assertEqual(res, res_test)
@@ -79,6 +83,7 @@ def test_recrule_str_until(self):
     def test_recrule_from_until(self):
         from datetime import datetime
         from plone.event.recurrence import recurrence_sequence_ical
+
         start = datetime(2011, 11, 23)
         recrule = None
         from_ = datetime(2011, 11, 1)
@@ -95,8 +100,9 @@ def test_recrule_from_until(self):
     def test_recrule_str_more_than_MAXCOUNT(self):
         from datetime import datetime
         from plone.event.recurrence import recurrence_sequence_ical
+
         start = datetime(2011, 11, 23)
-        recrule = 'FREQ=DAILY;INTERVAL=10;COUNT=1001'
+        recrule = "FREQ=DAILY;INTERVAL=10;COUNT=1001"
         seq = recurrence_sequence_ical(start, recrule=recrule)
         results = [res for res in seq]
         self.assertEqual(len(results), 1000)
@@ -104,8 +110,9 @@ def test_recrule_str_more_than_MAXCOUNT(self):
     def test_recrule_str_more_than_count(self):
         from datetime import datetime
         from plone.event.recurrence import recurrence_sequence_ical
+
         start = datetime(2011, 11, 23)
-        recrule = 'FREQ=DAILY;INTERVAL=10;COUNT=10'
+        recrule = "FREQ=DAILY;INTERVAL=10;COUNT=10"
         count = 5
         seq = recurrence_sequence_ical(start, recrule=recrule, count=count)
         results = [res for res in seq]
@@ -114,8 +121,9 @@ def test_recrule_str_more_than_count(self):
     def test_recrule_from(self):
         from datetime import datetime
         from plone.event.recurrence import recurrence_sequence_ical
+
         start = datetime(2011, 11, 23)
-        recrule = 'FREQ=DAILY;INTERVAL=1;COUNT=5'
+        recrule = "FREQ=DAILY;INTERVAL=1;COUNT=5"
         from_ = datetime(2011, 11, 25)
         until = datetime(2011, 11, 27)
         seq = recurrence_sequence_ical(
@@ -130,8 +138,9 @@ def test_recrule_from(self):
     def test_recrule_until(self):
         from datetime import datetime
         from plone.event.recurrence import recurrence_sequence_ical
+
         start = datetime(2011, 11, 24)
-        recrule = 'FREQ=DAILY;INTERVAL=1;COUNT=5'
+        recrule = "FREQ=DAILY;INTERVAL=1;COUNT=5"
         from_ = datetime(2011, 11, 23)
         until = datetime(2011, 11, 27)
         seq = recurrence_sequence_ical(
@@ -144,13 +153,13 @@ def test_recrule_until(self):
         self.assertEqual(len(results), 4)
 
     def test_recrule_from_until_with_duration(self):
-        """Should include events ranging into the queried timerange.
-        """
+        """Should include events ranging into the queried timerange."""
         from datetime import datetime
         from datetime import timedelta
         from plone.event.recurrence import recurrence_sequence_ical
+
         start = datetime(2011, 11, 23)
-        recrule = 'FREQ=DAILY;INTERVAL=1;COUNT=5'
+        recrule = "FREQ=DAILY;INTERVAL=1;COUNT=5"
         from_ = datetime(2011, 11, 26)
         until = datetime(2011, 11, 27)
         seq = recurrence_sequence_ical(
@@ -168,6 +177,6 @@ def test_recrule_until_with_timezone(self):
         from plone.event.recurrence import recurrence_sequence_ical
 
         start = datetime(2011, 11, 24)
-        recrule = 'RRULE:FREQ=DAILY;UNTIL=20111130T000000Z'
+        recrule = "RRULE:FREQ=DAILY;UNTIL=20111130T000000Z"
         seq = list(recurrence_sequence_ical(start, recrule=recrule))
         self.assertEqual(len(seq), 7)
diff --git a/plone/event/tests/test_recurrence_sequence_timedelta.py b/plone/event/tests/test_recurrence_sequence_timedelta.py
index fdb21af..9ca7210 100644
--- a/plone/event/tests/test_recurrence_sequence_timedelta.py
+++ b/plone/event/tests/test_recurrence_sequence_timedelta.py
@@ -5,6 +5,7 @@ class TestRecurrenceSequenceTimedelta(unittest.TestCase):
     def test_delta_None(self):
         from datetime import datetime
         from plone.event.recurrence import recurrence_sequence_timedelta
+
         start = datetime(2011, 11, 23)
         until = datetime(2011, 11, 24)
         td = recurrence_sequence_timedelta(start, until=until)
@@ -14,6 +15,7 @@ def test_delta_None(self):
     def test_delta_zero(self):
         from datetime import datetime
         from plone.event.recurrence import recurrence_sequence_timedelta
+
         start = datetime(2011, 11, 23)
         delta = 0
         until = datetime(2011, 11, 24)
@@ -24,6 +26,7 @@ def test_delta_zero(self):
     def test_until_None(self):
         from datetime import datetime
         from plone.event.recurrence import recurrence_sequence_timedelta
+
         start = datetime(2011, 11, 23)
         delta = 1
         td = recurrence_sequence_timedelta(start, delta=delta)
@@ -33,6 +36,7 @@ def test_until_None(self):
     def test_delta_an_hour_until_next_day(self):
         from datetime import datetime
         from plone.event.recurrence import recurrence_sequence_timedelta
+
         start = datetime(2011, 11, 23)
         delta = 60
         until = datetime(2011, 11, 24)
@@ -43,6 +47,7 @@ def test_delta_an_hour_until_next_day(self):
     def test_recur_more_than_MAXCOUNT(self):
         from datetime import datetime
         from plone.event.recurrence import recurrence_sequence_timedelta
+
         start = datetime(2011, 11, 23)
         delta = 1
         until = datetime(2012, 11, 23)
@@ -53,6 +58,7 @@ def test_recur_more_than_MAXCOUNT(self):
     def test_recur_more_than_count(self):
         from datetime import datetime
         from plone.event.recurrence import recurrence_sequence_timedelta
+
         start = datetime(2011, 11, 23)
         delta = 1
         until = datetime(2011, 11, 24)
diff --git a/plone/event/tests/test_utils.py b/plone/event/tests/test_utils.py
index 0576920..ca82a01 100644
--- a/plone/event/tests/test_utils.py
+++ b/plone/event/tests/test_utils.py
@@ -4,41 +4,47 @@
 
 
 class TestUtils(unittest.TestCase):
-    @mock.patch('plone.event.utils.pytz')
-    @mock.patch('plone.event.utils.os')
+    @mock.patch("plone.event.utils.pytz")
+    @mock.patch("plone.event.utils.os")
     def test_default_timezone(self, os, pytz):
         from plone.event.utils import default_timezone
-        os.environ.keys.return_value = ['TZ']
+
+        os.environ.keys.return_value = ["TZ"]
         os.environ = mock.MagicMock()
-        pytz.timezone().zone = 'zone'
-        self.assertEqual(default_timezone(), 'zone')
+        pytz.timezone().zone = "zone"
+        self.assertEqual(default_timezone(), "zone")
 
     def test_utcoffset_normalize(self):
         from plone.event.utils import utcoffset_normalize
+
         date = mock.Mock()
         date.replace = mock.Mock(side_effect=KeyError)
         self.assertEqual(utcoffset_normalize(date), date)
 
-    @mock.patch('plone.event.utils.guesstz')
-    @mock.patch('plone.event.utils.utctz')
+    @mock.patch("plone.event.utils.guesstz")
+    @mock.patch("plone.event.utils.utctz")
     def test_pydt__missing_zone_is_None(self, utctz, guesstz):
         from plone.event.utils import pydt
+
         dt = mock.Mock()
         dt.toZone.return_value = dt
         dt.parts.return_value = (2011, 11, 24, 11, 39, 00)
         guesstz.return_value = None
         import pytz
-        utctz.return_value = pytz.timezone('UTC')
+
+        utctz.return_value = pytz.timezone("UTC")
         pydt(dt)
         self.assertTrue(utctz.called)
 
-    @mock.patch('plone.event.utils.guesstz')
-    @mock.patch('plone.event.utils.utctz')
+    @mock.patch("plone.event.utils.guesstz")
+    @mock.patch("plone.event.utils.utctz")
     def test_pydt__missing_zone_is_not_None(self, utctz, guesstz):
         from plone.event.utils import pydt
+
         dt = mock.Mock()
         import pytz
-        utctz.return_value = pytz.timezone('UTC')
+
+        utctz.return_value = pytz.timezone("UTC")
         missing_zone = utctz()
         dt.toZone.return_value = dt
         dt.parts.return_value = (2011, 11, 24, 11, 39, 00)
@@ -48,16 +54,19 @@ def test_pydt__missing_zone_is_not_None(self, utctz, guesstz):
 
     def test_pydt__wrong_type(self):
         from plone.event.utils import pydt
-        self.assertEqual(pydt('wrongtype'), None)
+
+        self.assertEqual(pydt("wrongtype"), None)
 
     def test_dt2int_dt_is_None(self):
         from plone.event.utils import dt2int
+
         self.assertFalse(dt2int(None))
 
-    @mock.patch('plone.event.utils.MAX32', 0)
-    @mock.patch('plone.event.utils.utc')
+    @mock.patch("plone.event.utils.MAX32", 0)
+    @mock.patch("plone.event.utils.utc")
     def test_dt2int_less_MAX32(self, utc):
         from plone.event.utils import dt2int
+
         dt = mock.Mock()
         dd = mock.Mock()
         utc.return_value = dd
@@ -68,10 +77,11 @@ def test_dt2int_less_MAX32(self, utc):
         dd.minute = 16
         self.assertRaises(OverflowError, lambda: dt2int(dt))
 
-    @mock.patch('plone.event.utils.MAX32', 1077778937)
-    @mock.patch('plone.event.utils.utc')
+    @mock.patch("plone.event.utils.MAX32", 1077778937)
+    @mock.patch("plone.event.utils.utc")
     def test_dt2int_more_MAX32(self, utc):
         from plone.event.utils import dt2int
+
         dt = mock.Mock()
         dd = mock.Mock()
         utc.return_value = dd
diff --git a/setup.py b/setup.py
index 93f57df..b6ccb92 100644
--- a/setup.py
+++ b/setup.py
@@ -2,15 +2,13 @@
 from setuptools import setup
 
 
-version = '1.4.3.dev0'
+version = "1.4.3.dev0"
 
 setup(
-    name='plone.event',
+    name="plone.event",
     version=version,
     description="Event and calendaring related tools not bound to Plone",
-    long_description=(
-        open("README.rst").read() + "\n" + open("CHANGES.rst").read()
-    ),
+    long_description=(open("README.rst").read() + "\n" + open("CHANGES.rst").read()),
     classifiers=[
         "Development Status :: 5 - Production/Stable",
         "Framework :: Plone",
@@ -28,26 +26,28 @@
         "Programming Language :: Python :: 3.10",
         "Programming Language :: Python :: 3.11",
     ],
-    keywords='Plone calendar calendaring event recurring',
-    author='Plone Foundation',
-    author_email='plone-developers@lists.sourceforge.net',
-    url='https://github.com/plone/plone.event',
-    license='GPL',
+    keywords="Plone calendar calendaring event recurring",
+    author="Plone Foundation",
+    author_email="plone-developers@lists.sourceforge.net",
+    url="https://github.com/plone/plone.event",
+    license="GPL",
     packages=find_packages(),
-    namespace_packages=['plone'],
+    namespace_packages=["plone"],
     include_package_data=True,
     zip_safe=False,
-    python_requires='>=2.7,!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,!=3.4.*,!=3.5.*',
+    python_requires=">=2.7,!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,!=3.4.*,!=3.5.*",
     install_requires=[
-        'setuptools',
-        'python-dateutil',  # >4.0.2
-        'pytz',
-        'zope.component',
-        'zope.interface',
+        "setuptools",
+        "python-dateutil",  # >4.0.2
+        "pytz",
+        "zope.component",
+        "zope.interface",
     ],
-    extras_require={'test': [
-        'DateTime',
-        'mock',
-        'zope.configuration',
-    ], },
+    extras_require={
+        "test": [
+            "DateTime",
+            "mock",
+            "zope.configuration",
+        ],
+    },
 )