# File lib/rmail/message.rb, line 133
    def set_delimiters(delimiters, boundary)
      raise TypeError, "not a multipart message" unless multipart?
      raise ArgumentError, "delimiter array wrong size" unless
        delimiters.length == @body.length + 1
      @delimiters = delimiters.to_ary
      @delimiters_boundary = boundary.to_str
    end