get(key, fn = noop) {
const k = `${this.prefix}${key}`;
this.client.get(k, (err, data) => {
if (err) return fn(err);
if (!data) return fn(null, null);
data = data.toString();
try {
fn(null, JSON.parse(data));
} catch (e) {
fn(e);
}
});
}