ruby中最牛找方法定义的办法。(the strongest way to find where a ruby method defined)

让这个方法出错，然后在backtrace中就可以找到它是在哪里定义的了 ^_^ ( make error on this method on purpose, e.g. pass incorrect parameters, and you will see where it is defined )

refer to: http://stackoverflow.com/questions/13514597/where-does-the-underscore-syntax-in-typo-erb-files-come-from