def replace!(oth)
      if self.class != oth.class
        raise ArgumentError, "expected #{self.class} object"
      end

      component.each do |c|
        self.__send__("#{c}=", oth.__send__(c))
      end
    end
def replace!(oth)
      if self.class != oth.class
        raise ArgumentError, "expected #{self.class} object"
      end

      component.each do |c|
        self.__send__("#{c}=", oth.__send__(c))
      end
    end
replace self by other URI object