Rescue StandardError instead of Exception

It is bad style to rescue Exception, because it is the root of the
exception hierarchy, and includes SyntaxError, Interrupt, and Signal
Exception.

For more information see:
https://stackoverflow.com/questions/10048173/why-is-it-bad-style-to-rescue-exception-e-in-ruby
As far as I can see this would only ever raise a NoMethodError, which would be rescued by the new code. I don't see any reason to rescue Exception. If I'm wrong about that I'm happy to go back and change.