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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 delete_device_subscriptions(self, device_id):
 """Removes a device's subscriptions :param device_id: ID of the device (Required) :returns: None """

        api = self._get_api(mds.SubscriptionsApi)
        return api.delete_endpoint_subscriptions(device_id)