code: public function getProxy($className, $identifier)
      {
          $fqn = ClassUtils::generateProxyClassName($className, $this->proxyNamespace);
  
          if ( ! class_exists($fqn, false)) {
              $fileName = $this->getProxyFileName($className);
              if ($this->autoGenerate) {
                  $this->generateProxyClass($this->dm->getClassMetadata($className), $fileName, self::$proxyClassTemplate);
              }
              require $fileName;
          }
  
          if ( ! $this->dm->getMetadataFactory()->hasMetadataFor($fqn)) {
              $this->dm->getMetadataFactory()->setMetadataFor($fqn, $this->dm->getClassMetadata($className));
          }
  
          return new $fqn($this->dm, $identifier);
      }
docs: Gets a reference proxy instance for the entity of the given type and identified by
  the given identifier.
  
  @param string $className
  @param mixed $identifier
  @return object