./passgen.py -f d -b 012345678 results not as expected in '99999999'

[Videonauth]

In fact program hangs in an infinite loop. Breaking it results in following code:

./passgen.py -f d -b 012345678
==== Your password is ... ====
^CTraceback (most recent call last):
  File "./passgen.py", line 124, in <module>
    print(make_password(sanitize_input(parser.parse_args())))
  File "./passgen.py", line 86, in make_password
    tmp_char = random.choice(char_set)
  File "/usr/lib/python3.5/random.py", line 256, in choice
    return seq[i]
KeyboardInterrupt