code: def validate_line(self, line):
          
          line0 = line
          pos = 0
          while line:
              seg_m = self.ft.seg_regex.match(line)
              wsp_m = self.ws_punc_regex.match(line)
              if seg_m:
                  length = len(seg_m.group(0))
                  line = line[length:]
                  pos += length
              elif wsp_m:
                  length = len(wsp_m.group(0))
                  line = line[length:]
                  pos += length
              else:
                  msg = 'IPA not valid at position {} in "{}".'.format(pos, line0.strip())
                  # msg = msg.decode('utf-8')
                  print(msg, file=sys.stderr)
                  line = line[1:]
                  pos += 1
docs: Validate Unicode IPA string relative to panphon.
  
          line -- String of IPA characters. Can contain whitespace and limited
          punctuation.