def add_padding_0_bits(bits_string: str, required_length: int) -> tuple:
    """
    Adds 0 to bits string.
    Returns tuple - (bits string with padding, number of added 0s)
    """
    extra_0_bits_count = 0
    while len(bits_string) < required_length:
        bits_string += '0'
        extra_0_bits_count += 1
    return bits_string, extra_0_bits_count