code: def bad_signatures_to_str(error):
      
      return ", ".join("{}: {}".format(s.fpr,
                                       "Bad signature for key(s)")
                       for s in error.result.signatures
                       if s.status != NO_ERROR)
docs: Convert a bad signature exception to a text message.
      This is a workaround for gpg not handling non-ascii data correctly.
  
      :param BadSignatures error: BadSignatures exception