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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, group_id, mask=None):
 """Returns a PlacementGroup Object https://softlayer.github.io/reference/services/SoftLayer_Virtual_PlacementGroup/getObject """

        if mask is None:
            mask = "mask[id, name, createDate, rule, backendRouter[id, hostname]," \
                   "guests[activeTransaction[id,transactionStatus[name,friendlyName]]]]"
        return self.client.call('SoftLayer_Virtual_PlacementGroup', 'getObject', id=group_id, mask=mask)