code: def print_invalid_chars(invalid_chars, vargs):
      
      if len(invalid_chars) > 0:
          if vargs["print_invalid"]:
              print(u"".join(invalid_chars))
          if vargs["unicode"]:
              for u_char in sorted(set(invalid_chars)):
                  print(u"'%s'\t%s\t%s" % (u_char, hex(ord(u_char)), unicodedata.name(u_char, "UNKNOWN")))
docs: Print Unicode characterss that are not IPA valid,
      if requested by the user.
  
      :param list invalid_chars: a list (possibly empty) of invalid Unicode characters
      :param dict vargs: the command line parameters