get = async (key) => {
    const entry = await index.get(key)
    if (entry) {
      return entry.payload.value
    }
  }
Gets a value from the store by key.
@function
@param {string} key The key of the value to get.
@return {*} The value corresponding to key or null.
@memberof module:Databases.Databases-KeyValueIndexed
@instance