Simple Python password creator

password_creator.py

from itertools import cycle
from random import choice, shuffle
from string import ascii_lowercase, ascii_uppercase, digits, punctuation

def generate_password(length: int = 20, *, use_symbols: bool = True) -> str:
    """Generate random passwords, with or without symbols.

    Implementation ensures a fairly even balance of each character
    class, at the cost of entropy (e.g. for a four-character password
    with symbols there are only 5,191,680 possible combinations, rather
    than 78,074,896).

    >>> from random import seed
    >>> seed(0)
    >>> generate_password()
    'm7s;1)j[Yz^Q7G86#JiE'
    >>> generate_password(use_symbols=True)
    'o$3k0%M~0H:Q&xRg45Sz'
    >>> generate_password(use_symbols=False)
    'o15HGC4sfzpv42Tb9CYM'
    >>> generate_password(10)
    'SAc-5h9(Kp'
    >>> generate_password(10, use_symbols=True)
    'aDUs%3z8E#'
    >>> generate_password(10, use_symbols=False)
    'Ap01v8gGFn'
    >>> generate_password(0)
    ''
    >>> generate_password(-1)
    ''
    >>> generate_password("foo")
    Traceback (most recent call last):
      ...
    TypeError: 'str' object cannot be interpreted as an integer

    """
    cases = [ascii_lowercase, ascii_uppercase, digits]
    if use_symbols:
        cases.append(punctuation)
    characters = [
        choice(case)
        for _, case
        in zip(range(length), cycle(cases))
    ]
    shuffle(characters)
    return "".join(characters)

if __name__ == "__main__":
    import doctest
    doctest.testmod()