Remove SEQUENCE lines in VTIMEZONE (fixes #90)

CHANGELOG.rst

@@ -19,6 +19,7 @@ Ics.py changelog
  - Added LAST-MODIFIED attribute support
  - Event equality now checks all fields (except uid)
  - alarms in Event and Todo are now consistently lists and not a mix between set() and list()
+ - Fix SEQUENCE in VTIMEZONE error
 
 **************
 0.4

ics/icalendar.py

@@ -19,7 +19,7 @@
     ContentLine,
     Container,
 )
-from .utils import remove_x
+from .utils import remove_x, remove_sequence
 
 
 class Calendar(Component):
@@ -188,6 +188,7 @@ def timezone(calendar, vtimezones):
     """
     for vtimezone in vtimezones:
         remove_x(vtimezone)  # Remove non standard lines from the block
+        remove_sequence(vtimezone)  # Remove SEQUENCE lines because tzical does not understand them
         fake_file = StringIO()
         fake_file.write(str(vtimezone))  # Represent the block as a string
         fake_file.seek(0)

ics/utils.py

@@ -5,7 +5,6 @@
 
 from arrow.arrow import Arrow
 from datetime import timedelta
-from six import StringIO, string_types, text_type, integer_types
 
 from uuid import uuid4
 from dateutil.tz import gettz
@@ -24,6 +23,13 @@ def remove_x(container):
             del container[i]
 
 
+def remove_sequence(container):
+    for i in reversed(range(len(container))):
+        item = container[i]
+        if item.name == 'SEQUENCE':
+            del container[i]
+
+
 DATE_FORMATS = dict((len(k), k) for k in (
     'YYYYMM',
     'YYYYMMDD',

tests/fixture.py

@@ -503,6 +503,21 @@
 END:VCALENDAR
 """
 
+clas33 = """
+BEGIN:VTIMEZONE
+TZID:Australia/Sydney
+TZURL:http://tzurl.org/zoneinfo/Australia/Sydney
+SEQUENCE:498
+SEQUENCE:498
+BEGIN:STANDARD
+TZOFFSETFROM:+1100
+TZOFFSETTO:+1000
+TZNAME:EST
+DTSTART:20080406T030000
+RRULE:FREQ=YEARLY;BYMONTH=4;BYDAY=1SU
+END:STANDARD
+"""
+
 unfolded_cal2 = [
     'BEGIN:VCALENDAR',
     'BEGIN:VEVENT',

tests/misc.py

@@ -0,0 +1,6 @@
+from ics.icalendar import Calendar
+from .fixture import cal32
+
+
+def test_issue_90():
+    Calendar(cal32)