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let getSubscription: WebAPI.PushManagerAPI.pushManager => Promise.t< WebAPI.PushManagerAPI.pushSubscription,>
let permissionState: ( WebAPI.PushManagerAPI.pushManager, ~options: WebAPI.PushManagerAPI.pushSubscriptionOptionsInit=?,) => Promise.t<WebAPI.PushManagerAPI.permissionState>
let subscribe: ( WebAPI.PushManagerAPI.pushManager, ~options: WebAPI.PushManagerAPI.pushSubscriptionOptionsInit=?,) => Promise.t<WebAPI.PushManagerAPI.pushSubscription>