PartKeepr\UnitBundle\Entity\Unit::getPrefixes PHP Метод

    public function getPrefixes()
    {
        return $this->prefixes;
    }

 /**
  * Imports units.
  *
  * @return array An array with the keys "skipped" and "imported" which contain the number of units skipped and imported
  * @throws \Exception If an error occured
  */
 public function importUnits()
 {
     $path = $this->kernel->locateResource(self::UNIT_PATH . self::UNIT_DATA);
     $yaml = new Parser();
     $data = $yaml->parse(file_get_contents($path));
     $count = 0;
     $skipped = 0;
     foreach ($data as $unitName => $unitData) {
         $unit = $this->getUnit($unitName);
         if ($unit === null) {
             $unit = new Unit();
             $unit->setName($unitName);
             $unit->setSymbol($unitData["symbol"]);
             if (array_key_exists("prefixes", $unitData)) {
                 if (!is_array($unitData["prefixes"])) {
                     throw new \Exception($unitName . " doesn't contain a prefix list, or the prefix list is not an array.");
                 }
                 foreach ($unitData["prefixes"] as $name) {
                     $prefix = $this->getSiPrefix($name);
                     if ($prefix === null) {
                         throw new \Exception("Unable to find SI Prefix " . $name);
                     }
                     $unit->getPrefixes()->add($prefix);
                 }
             }
             $this->entityManager->persist($unit);
             $this->entityManager->flush();
             $count++;
         } else {
             $skipped++;
         }
     }
     return array("imported" => $count, "skipped" => $skipped);
 }