def family_constructor(c):
    """https://github.com/thom311/libnl/blob/libnl3_2_25/lib/genl/family.c#L37.

    Positional arguments:
    c -- nl_object-derived class instance.
    """
    family = c
    if not hasattr(family, 'gf_ops'):
        setattr(family, 'gf_ops', nl_list_head(container_of=family))
    if not hasattr(family, 'gf_mc_grps'):
        setattr(family, 'gf_mc_grps', nl_list_head(container_of=family))
    nl_init_list_head(family.gf_ops)
    nl_init_list_head(family.gf_mc_grps)