# File lib/spruz/string_version.rb, line 49
      def []=(index, value)
        value = value.to_i
        value >= 0 or raise ArgumentError, "version numbers can't contain negative numbers like #{value}"
        a = array
        @array = nil
        a[index] = value
        a.map! { |x| x.nil? ? 0 : x }
        @version.replace a * '.'
      end