--- Array(arg)

    arg.to_ary  arg.to_a ƤӽФư
    Ѵ̤֤ޤ
    Ѵ̤Ǥʤ㳰 TypeError ȯ
    ޤ

    ruby 1.7 feature:  nil ξ硢㳰
    TypeError ȯޤ

