get = async (hash) => {
    let value = await storage1.get(hash)
    if (!value) {
      value = await storage2.get(hash)
      if (value) {
        await storage1.put(hash, value)
      }
    }
    return value
  }
Gets data from the composed storage.

Get will fetch the data from storage1 first. If no value is found, an
attempt is made to fetch the data from storage2. If data exists in
storage2 but not in storage1, the data is added to storage1.
@function
@param {string} hash The hash of the data to get.
@memberof module:Storage.Storage-Composed
@instance