[ruby/optparse] Tutorial: explain custom argument converters (https://github.com/ruby/optparse/pull/19)
https://github.com/ruby/optparse/commit/385dd4322d
[ruby/optparse] Tutorial: explain custom argument converters (https://github.com/ruby/optparse/pull/19)
https://github.com/ruby/optparse/commit/385dd4322d