code: function verifyExpiration() {
      if (opt.removeExpired === false) return;
      let now = Date.now();
      Object.keys(SESSION_STORE).forEach((id) => {
        let item = SESSION_STORE[id];
        if (!item) return;
        if (now < item.e) return;
        delete SESSION_STORE[id];
      });
    }
docs: /* the file session will try to delete any expired sessions once every x minutes.