docs: def read_file(fname):
      """
      Read file, convert wildcards into regular expressions, skip empty lines
      and comments.
      """
      res = []
      try:
          with open(fname, 'r') as f:
              for line in f:
                  line = line.rstrip('\n').rstrip('\r')
                  if line and (line[0] != '#'):
                      regexline = ".*" + re.sub("\*", ".*", line) + ".*"
                      res.append(regexline.lower())
      except IOError:
          pass
      return res