Chaining exceptions with the raise from statement

In some cases, we may want to merge some seemingly unrelated exceptions into a single generic exception. It's common for a complex module to define a single generic Error exception which applies to many situations that can arise within the module.

Most of the time, the generic exception is all that's required. If the module's Error is raised, something didn't work.

Less frequently, we want the details for debugging or monitoring purposes. We might want to write them to a log, or include the details in an e-mail. In this case, we need to provide supporting details that amplify or extend the generic exception. We can do this by chaining from the generic exception to the root cause exception.

Getting ready

Assume we're writing some complex string processing. We'd like to treat a number of different kinds of detailed exceptions as a single generic error so that users of our software are insulated from the implementation details. We can attach details...