# File lib/ipaddress/ipv4.rb, line 632
    def supernet(new_prefix)
      raise ArgumentError, "Can't supernet a /1 network" if new_prefix < 1
      raise ArgumentError, "New prefix must be smaller than existing prefix" if new_prefix >= @prefix.to_i
      self.class.new(@address+"/#{new_prefix}").network
    end