def METHOD_NAME(
    self, mock_requests, webhook_serializer
):
    # Given
    payload = {"key": "value"}
    webhook_serializer.return_value.data = payload
    secret = "random_key"
    Webhook.objects.create(
        url="http://url.1.com",
        enabled=True,
        environment=self.environment,
        secret=secret,
    )
    expected_signature = hmac.new(
        key=secret.encode(),
        msg=json.dumps(payload).encode(),
        digestmod=hashlib.sha256,
    ).hexdigest()
    call_environment_webhooks(
        environment=self.environment,
        data={},
        event_type=WebhookEventType.FLAG_UPDATED,
    )
    # When
    _, kwargs = mock_requests.post.call_args_list[0]
    # Then
    received_signature = kwargs["headers"][FLAGSMITH_SIGNATURE_HEADER]
    assert hmac.compare_digest(expected_signature, received_signature) is True