def freeze_options
      @opts.freeze
      @opts.each_key { |key| @opts[key].freeze }
      @opts[:cookies].each_key { |key| @opts[:cookies][key].freeze } rescue nil
    end
def freeze_options
      @opts.freeze
      @opts.each_key { |key| @opts[key].freeze }
      @opts[:cookies].each_key { |key| @opts[:cookies][key].freeze } rescue nil
    end
Freeze the opts Hash so that no options can be modified
 once the crawl begins