public function nonce_field($key = '_wpnonce', $referrer = false, $echo = true){
        return wp_nonce_field($this->action, $key, $referrer, $echo);
    }
public function nonce_field($key = '_wpnonce', $referrer = false, $echo = true){
        return wp_nonce_field($this->action, $key, $referrer, $echo);
    }
public function nonce_field ( $ key = '_wpnonce' , $ referrer = false , $ echo = true ) { return wp_nonce_field ( $ this -> action , $ key , $ referrer , $ echo ) ; }
Echo nonce field

@param string $key Default _wpnonce
@param bool $referrer Default false.
@param bool $echo Default true
@return string
Echo nonce field