code: public function getClassName($identifier, $args = [])
      {
          if (isset($this->classes[$identifier])) {
              return $args ? vsprintf($this->classes[$identifier], $args) : $this->classes[$identifier];
          }
      }
docs: Answers the class name for the specified identifier.
  
  @param string $identifier
  @param array $args
  
  @return string