def family_compare(a, b, attrs, flags):
raise NotImplementedError<EOL>
https://github.com/thom311/libnl/blob/libnl3_2_25/lib/genl/family.c#L150.

    Positional arguments:
    a -- nl_object class instance.
    b -- nl_object class instance.
    attrs -- integer.
    flags -- integer.

    Returns:
    Integer.