format all int to same width

main.py

class int_fmt:
    digit_count: int
    def __init__(self, max_n: int) -> None:
        self.digit_count = len(str(max_n))
    def __call__(self, n: int) -> str:
        return '{n:0{w}d}'.format(n=n, w=self.digit_count)
        
fmt = int_fmt(100)
fmt(3)