/**
  * Create
  *
  *     https://api.e-conomic.com/secure/api1/EconomicWebService.asmx?op=Subscription_Create
  *
  *     subscriptionNumber               Subscription number for the subscription
  *     subscriptionName                 Subscription name for the subscription
  *     description                      Description for the subscription
  *     includeName                      Enables include name for the subscription (boolean)
  *     subscriptionInterval             Subscription interval for the subscription
  *     calendarYearBasis                Enables calendar year for the subscription (boolean)
  *     collection                       Collection for the subscription
  *     addPeriod                        Enables add period for the subscription (boolean)
  *     allowMoreThanOneForEachDebtor    Enables to allow more than one for each debitor for the subscription
  *
  * @param array $data
  * @return mixed
  */
 public function create(array $data)
 {
     $subscriptionHandle = $this->client->Subscription_Create($data)->Subscription_CreateResult;
     return $subscriptionHandle;
 }