/**
  * Validate that prices contain the currencies required by the channel
  *
  * @param ProductValueInterface $value
  * @param Constraint            $constraint
  *
  * @return null
  */
 protected function validatePrices(ProductValueInterface $value, Constraint $constraint)
 {
     $channel = $constraint->getChannel();
     $expectedCurrencies = array_map(function ($currency) {
         return $currency->getCode();
     }, $channel->getCurrencies()->toArray());
     foreach ($expectedCurrencies as $currency) {
         foreach ($value->getData() as $price) {
             if ($price->getCurrency() === $currency) {
                 if ($price->getData() === null) {
                     $this->context->addViolation($constraint->messageComplete);
                 }
             }
         }
     }
 }