: delete_all
: delete_all {|popmail| .... }
    оΥ᡼ƾõޤ
    ֥åͿ줿ȤϾõˤ POPMail ֥Ȥ
    ֥åϤޤ

        # example
        n = 1
        pop.delete_all do |m|
          File.open("inbox/#{n}") {|f| f.write m.pop }
          n += 1
        end

