from functools import reduce


def a2bits(chars: str) -> str:
    """Converts a string to its bits representation as a string of 0's and 1's.

    >>> a2bits("Hello World!")
    '010010000110010101101100011011000110111100100000010101110110111101110010011011000110010000100001'
    """
    return bin(reduce(lambda x, y: (x << 8) + y, (ord(c) for c in chars), 1))[
        3:
    ]