in src/request-parameters/RequestParametersBase.php [47:57]
final protected function getOptionalSpec<T as RequestParameter>(
classname<T> $class,
string $name,
): T {
invariant(
C\contains_key($this->optionalSpecs, $name),
'%s is not an optional parameter',
$name,
);
return self::getSpec($this->optionalSpecs, $class, $name);
}