integrations/google: Upgrade to argparse.

zulip/integrations/google/google-calendar

@@ -8,7 +8,7 @@ import dateutil.parser
 import httplib2
 import itertools
 import logging
-import optparse
+import argparse
 import os
 import pytz
 from six.moves import urllib
@@ -40,9 +40,9 @@ sent = set()  # type: Set[Tuple[int, datetime.datetime]]
 
 sys.path.append(os.path.dirname(__file__))
 
-parser = optparse.OptionParser(r"""
+parser = zulip.add_default_arguments(argparse.ArgumentParser(r"""
 
-%prog \
+google-calendar \
     --user foo@zulip.com \
     --calendar calendarID@example.calendar.google.com
 
@@ -55,10 +55,10 @@ parser = optparse.OptionParser(r"""
     revealed to local users through the command line.
 
     Depends on: google-api-python-client
-""")
+"""))
 
 
-parser.add_option('--interval',
+parser.add_argument('--interval',
                     dest='interval',
                     default=30,
                     type=int,
@@ -66,16 +66,14 @@ parser.add_option('--interval',
                     help='Minutes before event for reminder [default: 30]',
                     metavar='MINUTES')
 
-parser.add_option('--calendar',
+parser.add_argument('--calendar',
                     dest = 'calendarID',
                     default = 'primary',
                     type = str,
                     action = 'store',
                     help = 'Calendar ID for the calendar you want to receive reminders from.')
 
-parser.add_option_group(zulip.generate_option_group(parser))
-
-(options, args) = parser.parse_args()
+options = parser.parse_args()
 
 if not (options.zulip_email):
     parser.error('You must specify --user')