def _timestamp_extractor_cmu(self, staging_audio_basename,<EOL>str_timestamps_with_sil_conf):
filter_untimed = filter(lambda x: len(x) == <NUM_LIT:4>,<EOL>str_timestamps_with_sil_conf)<EOL>if filter_untimed != str_timestamps_with_sil_conf:<EOL><INDENT>self.__errors[<EOL>(time(), staging_audio_basename)<EOL>] = str_timestamps_with_sil_conf<EOL><DEDENT>str_timestamps = [<EOL>str_timestamp[:-<NUM_LIT:1>]<EOL>for str_timestamp in filter_untimed<EOL>if not any([letter in {"<STR_LIT:<>", "<STR_LIT:>>", "<STR_LIT:/>"}<EOL>for letter in '<STR_LIT>'.join(str_timestamp)])]<EOL>timestamps = list([<EOL>_WordBlock(<EOL>word=re.findall("<STR_LIT>", x[<NUM_LIT:0>])[<NUM_LIT:0>],<EOL>start=round(float(x[<NUM_LIT:1>]), <NUM_LIT:2>),<EOL>end=round(float(x[<NUM_LIT:2>]), <NUM_LIT:2>)<EOL>) for x in str_timestamps])<EOL>return timestamps<EOL>
Parameters
----------
str_timestamps_with_sil_conf : [[str, str, str, str]]
    Of the form [[word, starting_sec, ending_sec, confidence]]

Returns
-------
timestamps : [[str, float, float]]