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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 get_all_subscriptions(self, next_token=None):
 """ Get list of all subscriptions. :type next_token: string :param next_token: Token returned by the previous call to this method. """

        params = {'ContentType' : 'JSON'}
        if next_token:
            params['NextToken'] = next_token
        response = self.make_request('ListSubscriptions', params, '/', 'GET')
        body = response.read()
        if response.status == 200:
            return json.loads(body)
        else:
            boto.log.error('%s %s' % (response.status, response.reason))
            boto.log.error('%s' % body)
            raise self.ResponseError(response.status, response.reason, body)