I have some problems understanding the basics of classes and modules in
Ruby nd arg and options. How do you create a e g class that can take
some options, but leave them out if not needed? This is what I'm
familiar with now, sending along an arg to the method in a module.

module Abc
def self.test(arg)
puts arg
end
end


In this occasion I have to pass along a an arg, or nil, or there will an
error. But how do I design my module so I can pass options, or leave
them out if wanted? Like:

Abc.test(:color => 'red') or Abc.test()