public function load($generator, $key = NULL)
{
if (!is_callable($generator)) {
// back compatiblity
trigger_error(__METHOD__ . ': order of arguments has been swapped.', E_USER_DEPRECATED);
list($generator, $key) = [$key, $generator];
}
$class = $this->getClassName($key);
if (!class_exists($class, FALSE)) {
$this->loadFile($class, $generator);
}
return $class;
}