def inherited(subclass)
      [:steps, :failed_steps].each do |inheritable_attribute|
        instance_var = "@#{inheritable_attribute}"
        subclass.instance_variable_set(instance_var, instance_variable_get(instance_var).dup || [])
      end
    end
def inherited(subclass)
      [:steps, :failed_steps].each do |inheritable_attribute|
        instance_var = "@#{inheritable_attribute}"
        subclass.instance_variable_set(instance_var, instance_variable_get(instance_var).dup || [])
      end
    end
Callback, assure that we add steps from parent class