diff -r 13be42829771 Lib/calendar.py
--- a/Lib/calendar.py	Wed Oct 28 03:15:38 2015 -0400
+++ b/Lib/calendar.py	Wed Oct 28 20:34:54 2015 +0100
@@ -604,52 +604,55 @@
     return seconds
 
 
-def main(args):
-    import optparse
-    parser = optparse.OptionParser(usage="usage: %prog [options] [year [month]]")
-    parser.add_option(
+def main():
+    import argparse
+    parser = argparse.ArgumentParser(usage="usage: %(prog)s [options] [year [month]]")
+    parser.add_argument('year', type=int, nargs='?')
+    parser.add_argument('month', type=int, nargs='?')
+
+    parser.add_argument(
         "-w", "--width",
-        dest="width", type="int", default=2,
+        dest="width", type=int, default=2,
         help="width of date column (default 2, text only)"
     )
-    parser.add_option(
+    parser.add_argument(
         "-l", "--lines",
-        dest="lines", type="int", default=1,
+        dest="lines", type=int, default=1,
         help="number of lines for each week (default 1, text only)"
     )
-    parser.add_option(
+    parser.add_argument(
         "-s", "--spacing",
-        dest="spacing", type="int", default=6,
+        dest="spacing", type=int, default=6,
         help="spacing between months (default 6, text only)"
     )
-    parser.add_option(
+    parser.add_argument(
         "-m", "--months",
-        dest="months", type="int", default=3,
+        dest="months", type=int, default=3,
         help="months per row (default 3, text only)"
     )
-    parser.add_option(
+    parser.add_argument(
         "-c", "--css",
         dest="css", default="calendar.css",
         help="CSS to use for page (html only)"
     )
-    parser.add_option(
+    parser.add_argument(
         "-L", "--locale",
         dest="locale", default=None,
         help="locale to be used from month and weekday names"
     )
-    parser.add_option(
+    parser.add_argument(
         "-e", "--encoding",
         dest="encoding", default=None,
         help="Encoding to use for output."
     )
-    parser.add_option(
+    parser.add_argument(
         "-t", "--type",
         dest="type", default="text",
         choices=("text", "html"),
         help="output type (text or html)"
     )
 
-    (options, args) = parser.parse_args(args)
+    options = parser.parse_args()
 
     if options.locale and not options.encoding:
         parser.error("if --locale is specified --encoding is required")
@@ -667,31 +670,28 @@
             encoding = sys.getdefaultencoding()
         optdict = dict(encoding=encoding, css=options.css)
         write = sys.stdout.buffer.write
-        if len(args) == 1:
+        if options.year and options.month:
+            write(cal.formatyearpage(options.year, **optdict))
+        else:
             write(cal.formatyearpage(datetime.date.today().year, **optdict))
-        elif len(args) == 2:
-            write(cal.formatyearpage(int(args[1]), **optdict))
-        else:
-            parser.error("incorrect number of arguments")
-            sys.exit(1)
     else:
         if options.locale:
             cal = LocaleTextCalendar(locale=locale)
         else:
             cal = TextCalendar()
         optdict = dict(w=options.width, l=options.lines)
+
+        args = [arg for arg in (sys.argv[0], options.year, options.month) if arg]
         if len(args) != 3:
-            optdict["c"] = options.spacing
-            optdict["m"] = options.months
-        if len(args) == 1:
+            optdict['c'] = options.spacing
+            optdict['m'] = options.months
+
+        if options.month:
+            result = cal.formatmonth(options.year, options.month, **optdict)
+        elif options.year:
+            result = cal.formatyear(options.year, **optdict)
+        else:
             result = cal.formatyear(datetime.date.today().year, **optdict)
-        elif len(args) == 2:
-            result = cal.formatyear(int(args[1]), **optdict)
-        elif len(args) == 3:
-            result = cal.formatmonth(int(args[1]), int(args[2]), **optdict)
-        else:
-            parser.error("incorrect number of arguments")
-            sys.exit(1)
         write = sys.stdout.write
         if options.encoding:
             result = result.encode(options.encoding)
@@ -700,4 +700,4 @@
 
 
 if __name__ == "__main__":
-    main(sys.argv)
+    main()