require 'logger'
require 'pp'

class Base
  def initialize
    @@logger = Logger.new(STDOUT)
  end
end

class Helper < Base
  def initialize
    super()
  end
  def run
    pp @@logger.level
  end
end

class Main < Base
  def initialize
    super()
  end
  def run
    pp @@logger.level
    @@logger.level = 'warn'
    pp @@logger.level
    c = Helper.new
    c.run
  end
end

p = Main.new
p.run