def base_repr(number: int, base: int = 10, padding: int = 0) -> str:
    """
    Return a string representation of a number in the given base system.
    """
    digits = "0123456789abcdefghijklmnopqrstuvwxyz"
    if base > len(digits):
        raise ValueError("Bases greater than 36 not handled in base_repr.")
    elif base < 2:
        raise ValueError("Bases less than 2 not handled in base_repr.")

    num = abs(number)
    res = []
    while num:
        res.append(digits[num % base])
        num //= base
    if padding:
        res.append("0" * padding)
    if number < 0:
        res.append("-")
    return "".join(reversed(res or "0"))