class Selenium::WebDriver::Support::RelativeLocator

def as_json
  {
    relative: {
      root: @root,
      filters: @filters.map do |kind, filter|
        {
          kind: kind,
          args: [filter]
        }
      end
    }
  }
end

def initialize(locator)
  @filters, @root = locator.partition { |how, _| KEYS.include?(how) }.map(&:to_h)
end