module A
  extend self
  def super_wazna_metoda; puts "jestem wazna"; end
  def mniej_wazna_metoda1; end
  def mniej_wazna_metoda2; end
  def mniej_wazna_metoda3; end
  def mniej_wazna_metoda4; end
  def mniej_wazna_metoda5; end
end

module B
  include A
  def self.foo
    A.super_wazna_metoda
  end

  def bar
    super_wazna_metoda
  end

end

class Tester
  include B
end

def test_tester_class_metod
  Tester.super_wazna_metoda => "jestem wazna"
end

def test_tester_instance_method
  Tester.new.super_wazna_metoda => "jestem wazna"
end