code: public function generateProxyClasses(array $classes, $toDir = null)
      {
          $proxyDir = $toDir ?: $this->proxyDir;
          $proxyDir = rtrim($proxyDir, DIRECTORY_SEPARATOR) . DIRECTORY_SEPARATOR;
          foreach ($classes as $class) {
              /* @var $class ClassMetadata */
              if ($class->isMappedSuperclass) {
                  continue;
              }
  
              $proxyFileName = $this->getProxyFileName($class->name, $toDir);
              $this->generateProxyClass($class, $proxyFileName, self::$proxyClassTemplate);
          }
      }
docs: Generates proxy classes for all given classes.
  
  @param array $classes The classes (ClassMetadata instances) for which to generate proxies.
  @param string $toDir The target directory of the proxy classes. If not specified, the
  directory configured on the Configuration of the DocumentManager used
  by this factory is used.