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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def calendars(self):
 """ Retrieves calendars for this month """

        today = datetime.today()
        first_day, last_day = monthrange(today.year, today.month)
        from_dt = datetime(today.year, today.month, first_day)
        to_dt = datetime(today.year, today.month, last_day)
        params = dict(self.params)
        params.update({
            'lang': 'en-us',
            'usertz': get_localzone().zone,
            'startDate': from_dt.strftime('%Y-%m-%d'),
            'endDate': to_dt.strftime('%Y-%m-%d')
        })
        req = self.session.get(self._calendars, params=params)
        self.response = req.json()
        return self.response['Collection']