[casualsuperman2]

And then in the code for handling the error, you can do

   switch err.(type) {
      case db.IOError:
          // Database exception here
      case io.FileNotFoundError:
          // File exception
      default:
          // Pass it to our caller for them to handle.
          return nil, err
   }

Which gives you the ability to selectively catch errors based on type.