def _next_month(self):
self._canvas.place_forget()<EOL>year, month = self._date.year, self._date.month<EOL>self._date = self._date + self.timedelta(<EOL>days=calendar.monthrange(year, month)[<NUM_LIT:1>] + <NUM_LIT:1>)<EOL>self._date = self.datetime(self._date.year, self._date.month, <NUM_LIT:1>)<EOL>self._build_calendar()<EOL>
Update calendar to show the next month.