gistfile1.txt

class A
  def initialize(a:)
    puts("Initailize A: #{a}")
  end
end

class B < A
  def initialize(a:, b:)
    puts("Initailize B: #{b}")
    super(a)
  end
end

class C < B
  def initialize(a:, b:, c:)
    puts("Initailize C: #{c}")
    super(a, b)
  end
end

c = C.new(a: 1, b: 2, c: 3)

⇒  ruby test.rb
Initailize C: 3
test.rb:8:in `initialize': wrong number of arguments (given 2, expected 0; required keywords: a, b) (ArgumentError)
        from test.rb:17:in `initialize'
        from test.rb:21:in `new'
        from test.rb:21:in `<main>'

gistfile2.txt

class A
  def initialize(a)
    puts("Initailize A: #{a}")
  end
end

class B < A
  def initialize(a, b)
    puts("Initailize B: #{b}")
    super(a)
  end
end

class C < B
  def initialize(a, b, c)
    puts("Initailize C: #{c}")
    super(a, b)
  end
end


⇒  ruby test.rb
Initailize C: 3
Initailize B: 2
Initailize A: 1