def crc_calc(input_string):
    """
    Calculates cumulative XOR CRC of inputted string
    :param input_string: Str to CRC
    :return: 2 char CRC str
    """
    crc = 0

    for next_char in input_string:
        ascii_val = ord(next_char)
        crc ^= ascii_val

    hex_crc = hex(crc)

    if crc <= 0xF:
        crc_byte = '0' + hex_crc[2]
    else:
        crc_byte = hex_crc[2:4]

    return crc_byte