public function getReturnUrls(string $key = null)
    {
        return $key
            ? $this->returnUrls[$key] ?? null
            : $this->returnUrls;
    }
public function getReturnUrls(string $key = null)
    {
        return $key
            ? $this->returnUrls[$key] ?? null
            : $this->returnUrls;
    }
public function getReturnUrls ( string $ key = null ) { return $ key ? $ this -> returnUrls [ $ key ] ?? null : $ this -> returnUrls ; }
Get the Return URLs

@param string $key
@return array
Get the Return URLs