SEQUENCE: in VTIMEZONE causes backtrace

[wom-bat]

I have an ics feed from Confluence. It contains things like:

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

which causes a python backtrace an d error:

` File "./icsfeed.py", line 36, in get_todays_events
    c = Calendar(urlopen(url).read().decode('iso-8859-1'))
  File "/usr/local/lib/python2.7/dist-packages/ics/icalendar.py", line 71, in __init__
    self._populate(container[0])  # Use first calendar
  File "/usr/local/lib/python2.7/dist-packages/ics/component.py", line 52, in _populate
    extractor.function(self, lines)  # Send a list or empty list
  File "/usr/local/lib/python2.7/dist-packages/ics/icalendar.py", line 223, in timezone
    timezones = tzical(fake_file)  # tzical does not like strings
  File "/usr/lib/python2.7/dist-packages/dateutil/tz/tz.py", line 748, in __init__
    self._parse_rfc(fileobj.read())
  File "/usr/lib/python2.7/dist-packages/dateutil/tz/tz.py", line 891, in _parse_rfc
    raise ValueError("unsupported property: "+name)
ValueError: unsupported property: SEQUENCE

[ksalman]

I am also seeing this issue.

[jc1518]

me too.

[snoopyjc]

Same here!!! Any avoidance?

[snoopyjc]

Avoidance: Send text thru this before feeding to Calendar():

@staticmethod
def _remove_sequence_from_vtimezone(text):   # Avoid BUG: https://github.com/C4ptainCrunch/ics.py/issues/90
    result = ''
    lines = text.split('\n')
    in_vt = False
    for i in reversed(range(len(lines))):
        line = lines[i]
        if in_vt:
            if line.startswith('SEQUENCE:'):
                #print(f'del SEQUENCE at line {i}')
                del lines[i]
            elif line.startswith('BEGIN:VTIMEZONE'):
                #print(f'not in_vt at line {i}')
                in_vt = False
        elif line.startswith('END:VTIMEZONE'):
            #print(f'in_vt at line {i}')
            in_vt = True
    return '\n'.join(lines)