def _bit_str_pad(base_str: str, req_len: int, pad_type: str='0') -> str:
    """ Pads the left side of a string with pad_type
    Args:
        base_str: The string to add padding to
        req_len: The total required length of the string
        pad_type: What to pad the string with

    Returns:
        A left padded string based on the required length

    """
    for x in range(len(base_str), req_len):
        base_str = pad_type + base_str
    return base_str