# File lib/mash.rb, line 217
  def stringify_keys!
    keys.each{|k| 
      v = delete(k)
      self[k.to_s] = v
      v.stringify_keys! if v.is_a?(Hash)
      v.each{|p| p.stringify_keys! if p.is_a?(Hash)} if v.is_a?(Array)
    }
    self
  end