How to use the pywebpush.WebPusher function in pywebpush

for target in list(targets):
            info = self.registrations.get(target)
            try:
                info = REGISTER_SCHEMA(info)
            except vol.Invalid:
                _LOGGER.error(
                    "%s is not a valid HTML5 push notification" " target", target
                )
                continue
            payload[ATTR_DATA][ATTR_JWT] = add_jwt(
                timestamp,
                target,
                payload[ATTR_TAG],
                info[ATTR_SUBSCRIPTION][ATTR_KEYS][ATTR_AUTH],
            )
            webpusher = WebPusher(info[ATTR_SUBSCRIPTION])
            if self._vapid_prv and self._vapid_email:
                vapid_headers = create_vapid_headers(
                    self._vapid_email, info[ATTR_SUBSCRIPTION], self._vapid_prv
                )
                vapid_headers.update({"urgency": priority, "priority": priority})
                response = webpusher.send(
                    data=json.dumps(payload), headers=vapid_headers, ttl=ttl
                )
            else:
                # Only pass the gcm key if we're actually using GCM
                # If we don't, notifications break on FireFox
                gcm_key = (
                    self._gcm_key
                    if "googleapis.com" in info[ATTR_SUBSCRIPTION][ATTR_ENDPOINT]
                    else None
                )

Desc: Web Push notifications for Chrome and FireFox

    Installation:
    pip install 'pywebpush>=0.4.0'
    """

    subscription_info = kwargs.pop('subscription_info')

    payload = {
        "title": kwargs.pop("event"),
        "body": message,
        "url": kwargs.pop("push_url", None)
    }
    payload.update(kwargs)

    wp = WebPusher(subscription_info)
    response = wp.send(
        dumps(payload), gcm_key=settings.GCM_KEY,
        ttl=kwargs.pop("ttl", 60))

    if not response.ok or (
            response.text and loads(response.text).get("failure") > 0):
        raise GCMError(response.text)
    return True

for registration in registrations:
        user_subscriptions, count = request.registry.storage.get_all(
            collection_id=SUBSCRIPTION_COLLECTION_ID,
            parent_id=registration['id'])
        subscriptions += user_subscriptions

    for subscription in subscriptions:
        # Remove the subscription id if present.
        subscription.pop('id', None)
        # Remove the subscription last_modified value if present.
        subscription.pop('last_modified')
        data = request.validated.get('data')
        if data:
            data = canonical_json(data)
        push_initialize = WebPusher(subscription)
        push_initialize.send(data=data, ttl=15)

    request.response.status = 202
    return {"code": 202, "message": "Accepted"}

def process_record(self, new, old=None):
        new = super(Subscription, self).process_record(new, old)
        try:
            WebPusher(new)
        except WebPushException as e:
            raise http_error(HTTPBadRequest(),
                             errno=ERRORS.INVALID_PARAMETERS,
                             message='Invalid subscription: %s' % e)
        return new