# File lib/scrubyt/core/shared/extractor.rb, line 16
    def self.define(mode=nil, &extractor_definition)
      if mode.is_a?(Hash)
        if mode[:agent]==:firefox
          FetchAction.class_eval do
            include Navigation::Firewatir
          end
        else
          FetchAction.class_eval do
            include Navigation::Mechanize
          end
        end
      else
        FetchAction.class_eval do
          include Navigation::Mechanize
        end
      end
      extractor = self.new(mode, extractor_definition)
      extractor.result
    end