protected function compileIn($key, $masque)
    {
        if (!preg_match("/^in:(.+)$/", $masque, $match)) {
            return;
        }

        $values = explode(",", end($match));

        foreach ($values as $index => $value) {
            $values[$index] = trim($value);
        }

        if (in_array($this->inputs[$key], $values)) {
            return;
        }

        $this->last_message = $this->lexique('in', [
            'attribute' => $key,
            'value' => implode(", ", $values)
        ]);

        $this->fails = true;

        $this->errors[$key][] = [
            "masque" => $masque,
            "message" => $this->last_message
        ];
    }