    uint8 feedDecimals = feeds[token].feed.decimals();  // 18 => [ETH/DAI] https://rinkeby.etherscan.io/address/0x74825dbc8bf76cc4e9494d0ecb210f676efa001d#readContract
    uint8 tokenDecimals = feeds[token].tokenDecimals;   // > 18
    uint8 decimals = 36 - feedDecimals - tokenDecimals; // overflow
