public function ListManagement_Create_List($modifyList) {
        $ret = false;

        if ($modifyList instanceof \Yesmail\YesmailListManagementModifyList && $modifyList->is_valid() === true) {
            $ret = $this->_call_api('post', "{$this->_url}/lists/{$modifyList->type}", $modifyList);
        }

        return $ret;
    }