murajun_sample.rb

class Murajun
  def initialize(name)
    @name = name
  end
  
  def murajun?
    @name == "murajun"
  end
end

class Name
  def hello_murajun(name)
    if name.murajun?
      "Hello, murajun."
    else
      "You're not murajun."
    end
  end
end

murajun = Murajun.new("murajun1978")

name = Name.new
p name.hello_murajun(murajun) # => You're not murajun.