fun historicalPrices(id: String): LiveData<List<HistoricalPrice>>
Returns a LiveData containing a List of HistoricalPrices for the requested id or null if no such HistoricalPrices exists.
id - The id of the requested HistoricalPrices.
Return
LiveData containing a List of HistoricalPrices for the requested id or null if no such HistoricalPrices exists.