public function getMultiple(string ...$keys): array
    {
        $ret = [];
        foreach ($keys as $key) {
            $ret[] = $this->get($key);
        }
        return $ret;
    }
public function getMultiple(string ...$keys): array
    {
        $ret = [];
        foreach ($keys as $key) {
            $ret[] = $this->get($key);
        }
        return $ret;
    }
public function getMultiple ( string ... $ keys ) : array { $ ret = [ ] ; foreach ( $ keys as $ key ) { $ ret [ ] = $ this -> get ( $ key ) ; } return $ ret ; }
Get multiple header values

@param string ...$keys
@return array<string>
Get multiple header values