def cmp(other)
			if (!other.kind_of?(IPv4))
				raise ArgumentError, "Expected an IPv4 object for 'other' but got a #{other.class}."
			end
			if (self.addr > other.addr)
				return 1
			elsif (self.addr < other.addr)
				return -1
			end
			return 0
		end
def cmp(other)
			if (!other.kind_of?(IPv4))
				raise ArgumentError, "Expected an IPv4 object for 'other' but got a #{other.class}."
			end
			if (self.addr > other.addr)
				return 1
			elsif (self.addr < other.addr)
				return -1
			end
			return 0
		end
cmp compares equality with another IPv4. Return:
* 1 if this IPv4 is numerically greater
* 0 if the two are equal
* -1 if this IPv4 is numerically less