A Price Oracle is a contract that returns the price for any given asset pair. Price is retrieved either directly from an oracle, calculated using common asset pairs, or uses external data to calculate price. Note: Prices are returned in preciseUnits (i.e. 18 decimals of precision).
mapping(address => mapping(address => IOracle)) public oracles;
Mapping between assetA / assetB and its associated oracle. Asset 1 -> asset 2 -> source oracle address.