def assert_no_404_errors(self, multithreaded=True):
links = self.get_unique_links()<EOL>if multithreaded:<EOL><INDENT>from multiprocessing.dummy import Pool as ThreadPool<EOL>pool = ThreadPool(<NUM_LIT:10>)<EOL>pool.map(self.assert_link_status_code_is_not_404, links)<EOL>pool.close()<EOL>pool.join()<EOL><DEDENT>else:<EOL><INDENT>for link in links:<EOL><INDENT>self.assert_link_status_code_is_not_404(link)<EOL><DEDENT><DEDENT>
Assert no 404 errors from page links obtained from:
            "a"->"href", "img"->"src", "link"->"href", and "script"->"src".