key chain with polymorphism and single responsibility

key_chain.rb

class BedroomKeyGenerator
  def self.generate
    "algorithm of bedroom key" * 3
  end
end

class FrontDoorKeyGenerator
  def self.generate
    "algorithm of front_door key" * 3
  end
end

class BathroomKeyGenerator
  def self.generate
    "algorithm of bathroom key" * 3
  end
end

class KeyChain
  def initialize(door)
    @door = door
  end

  def get
    {
      bedroom: BedroomKeyGenerator,
      front_door: FrontDoorKeyGenerator,
      bathroom: BathroomKeyGenerator
    }.fetch(door).generate
  end

  private

  attr_reader :door
end