/**
  * @param Merchant $merchant
  *
  * @return Merchant
  */
 public function addMerchant(Merchant $merchant)
 {
     if (!isset($this->merchants[$merchant->name()])) {
         $this->merchants[$merchant->name()] = $merchant;
     }
     return $this->merchants[$merchant->name()];
 }
 /**
  * @param Merchant $merchant
  *
  * @return array
  */
 private function merchantExists(Merchant $merchant)
 {
     return $this->findBy(['name' => $merchant->name()]);
 }