Config::NotDefined inherits from KeyError
Config::NotDefined inherits from KeyError

The thinking here is that when calling Config.fetch you might expect
that it'd raise KeyError (like Hash#fetch) does if the config setting
you want isn't defined. So we do.

cao7113/nesta,gma/nesta,nathandao/ginatra_dummy_2,nathandao/ginatra_dummy_2,nathandao/ginatra_dummy_2