def break_up_ipv4_address_space(num_threads=8):
    """
    >>> break_up_ipv4_address_space() == \
     [('0.0.0.0', '31.255.255.255'), ('32.0.0.0', '63.255.255.255'),\
     ('64.0.0.0', '95.255.255.255'), ('96.0.0.0', '127.255.255.255'),\
     ('128.0.0.0', '159.255.255.255'), ('160.0.0.0', '191.255.255.255'),\
     ('192.0.0.0', '223.255.255.255'), ('224.0.0.0', '255.255.255.255')]
    True
    """
    ranges = []

    multiplier = 256 / num_threads

    for marker in range(0, num_threads):
        starting_class_a = (marker * multiplier)
        ending_class_a = ((marker + 1) * multiplier) - 1
        ranges.append(('%d.0.0.0' % starting_class_a,
                       '%d.255.255.255' % ending_class_a))

    return ranges