❯ irb
irb(main):001:0> require './safe_load.rb'
=> true
irb(main):002:0> Marshal.safe_load(Marshal.dump({cat: "black"}))
=> {:cat=>"black"}
irb(main):003:0> Marshal.load(Marshal.dump(Module))
=> Module
irb(main):004:0> Marshal.safe_load(Marshal.dump(Module))
...
StandardError (unexepected type Class)
# テスト実行
ruby test.rb