tell_dont_ask_example.rb

class User
   def initialize(name, user_information={})
     @name = name
     @phone_number = user_information[:phone_number] || NullPhoneNumber.new
   end

   def name
     @name
   end

   def phone_number
     @phone_number.to_s
   end
end

class NullPhoneNumber
  def to_s
    'No phone number provided'
  end
end

user = User.new 'Brayan'
puts user.phone_number