code: public function getVoiceConsumptions($params = null)
      {
      	$consumptionList = json_decode(self::getClient()->getVoiceConsumptions($this->service, $this->billingAccount, $params));
      	$consumptions = array();
  
      	foreach ($consumptionList as $consumption) 
      	{
      		$consumptions[] = new VoiceConsumption($consumption, $this);
      	}
      	return $consumptions;
      }
docs: Get Call delivery records.
  @return [type] [description]