How should module calculations return errors?
Since the name of the function calculate/3 doesn’t end with ! and returns a raw value instead of an ok/error tuple, I’m just checking whether it’s OK for my custom calculation (defined in its own module) to raise an error which can be caused by, say, an attribute having a value of an unexpected type or an invalid string format (this would be caused by a bug in the app — I’m not trying to code a validation in a calculation).
