# File lib/rack/utils.rb, line 84
    def parse_nested_query(qs, d = nil)
      params = KeySpaceConstrainedParams.new

      (qs || '').split(d ? /[#{d}] */n : DEFAULT_SEP).each do |p|
        k, v = p.split('=', 2).map { |s| unescape(s) }

        normalize_params(params, k, v)
      end