code: def visit?(url)
        !visited?(url) &&
         visit_scheme?(url.scheme) &&
         visit_host?(url.host) &&
         visit_port?(url.port) &&
         visit_link?(url.to_s) &&
         visit_url?(url) &&
         visit_ext?(url.path) &&
         robot_allowed?(url.to_s)
      end
docs: Determines if a given URL should be visited.
  
   @param [URI::HTTP] url
     The URL in question.
  
   @return [Boolean]
     Specifies whether the given URL should be visited.