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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_object(self, identifier, mask=None):
 """Get a Reserved Capacity Group :param int identifier: Id of the SoftLayer_Virtual_ReservedCapacityGroup :param string mask: override default object Mask """

        if mask is None:
            mask = "mask[instances[billingItem[item[keyName],category], guest], backendRouter[datacenter]]"
        result = self.client.call(self.rcg_service, 'getObject', id=identifier, mask=mask)
        return result