def RecognizeCLFLine(self, line):
    match = ACCESSLOG_CLF_PATTERN.match(line)
    recognize = match and (match.group(1) in ('HEAD', 'GET'))
    if recognize:
      output.Log('Recognized a Common Logfile Format file.', 2)
    return recognize
  #end def RecognizeCLFLine
Try to tokenize a logfile line according to CLF pattern and see if
dataset/ETHPy150Open benoitc/restkit/doc/sitemap_gen.py/InputAccessLog.RecognizeCLFLine