def lookup_family(family):
    """https://github.com/thom311/libnl/blob/libnl3_2_25/lib/genl/mngt.c#L94.

    Positional arguments:
    family -- integer.

    Returns:
    genl_ops class instance or None.
    """
    for ops in nl_list_for_each_entry(genl_ops(), genl_ops_list, 'o_list'):
        if ops.o_id == family:
            return ops
    return None