How to throw the “We need ftp info” at a user

simple function:

    protected function _cred_check(){
    $aisis_file_system_structure = WP_Filesystem();
    if($aisis_file_system_structure == false){
        echo '<div class="alert"><strog>NOTE!</strong> We need your ftp creds before we continue!</div>';
        return true;
    }        

    return false;
}

then do:

if($this->_cred_check()){
    request_filesystem_credentials('your/link/to/your/update/page');
}else{ // your update stuff }