# File lib/hashie/mash.rb, line 149
   def method_missing(method_name, *args, &blk)
     return self.[](method_name, &blk) if key?(method_name)
     match = method_name.to_s.match(/(.*?)([?=!]?)$/)
     case match[2]
     when "="
       self[match[1]] = args.first
     when "?"
       !!self[match[1]]
     when "!"
       initializing_reader(match[1])
     else
       default(method_name, *args, &blk)
     end
   end