def random(self, length=None):
if length is None:<EOL><INDENT>length = self._length<EOL><DEDENT>random_num = int(binascii.b2a_hex(os.urandom(length)), <NUM_LIT:16>)<EOL>return int_to_string(random_num, self._alphabet, padding=length)[:length]<EOL>
Generate and return a cryptographically-secure short random string
of the specified length.