gistfile1.rb

class A
  def self.say(msg)
    puts "Hello from A #{msg}"
  end
end

class B < A
  def self.say(msg)
    if msg.empty?
      super
    else
      puts msg
    end
  end
end

# B.say 'hi' >> 'hi'
# B.say ''   >> 'Hello from A '

# You don't have to call super with the required argument(s), it gets those passed along,
# but if you want to...you can explicitly pass args using super(args)