    # File lib/compass/sass_extensions/functions/lists.rb, line 68
      def _compass_slice(list, start_index, end_index = nil)
        end_index ||= Sass::Script::Number.new(-1)
        start_index = start_index.value
        end_index = end_index.value
        start_index -= 1 unless start_index < 0
        end_index -= 1 unless end_index < 0
        Sass::Script::List.new list.values[start_index..end_index], list.separator
      end