def summ(other)
			if (!other.kind_of?(IPv4Net))
				raise ArgumentError, "Expected an IPv4Net object for 'other' but got a #{other.class}."
			end
			
			# netmasks must be identical
			if (self.netmask.prefix_len != other.netmask.prefix_len)
				return nil
			end
			
			# merge-able networks will be identical if you right shift them by the number of bits in the hostmask + 1
			shift = 32 - self.netmask.prefix_len + 1
			addr = self.network.addr >> shift
			otherAddr = other.network.addr >> shift
			if (addr != otherAddr)
				return nil
			end
			return self.resize(self.netmask.prefix_len - 1)
		end
def summ(other)
			if (!other.kind_of?(IPv4Net))
				raise ArgumentError, "Expected an IPv4Net object for 'other' but got a #{other.class}."
			end
			
			# netmasks must be identical
			if (self.netmask.prefix_len != other.netmask.prefix_len)
				return nil
			end
			
			# merge-able networks will be identical if you right shift them by the number of bits in the hostmask + 1
			shift = 32 - self.netmask.prefix_len + 1
			addr = self.network.addr >> shift
			otherAddr = other.network.addr >> shift
			if (addr != otherAddr)
				return nil
			end
			return self.resize(self.netmask.prefix_len - 1)
		end
summ creates a summary address from this IPv4Net and another.
 It returns nil if the two networks are incapable of being summarized.