public function webhook(array $data = []): ?array
    {
        $validated = $this->validateAgainstSignature($data, $this->client->getSignatureKey(), [
            'amount', 'collection_id', 'due_at', 'email', 'id', 'mobile', 'name',
            'paid_amount', 'paid_at', 'paid', 'state', 'url',
        ]);

        if ((bool) $validated) {
            return $this->filterResponse($data);
        }

        return null;
    }