code: public function loadMetadataForClass($className)
      {
          foreach ($this->drivers as $namespace => $driver) {
              if (strpos($className, $namespace) === 0) {
                  return $driver->loadMetadataForClass($className);
              }
          }
  
          return null;
      }
docs: Loads the metadata for the specified class
  
  @param string $className The name of the class.
  
  @return ClassMetadata|null The metadata for the specified class or null.