def fill_blanks(aut, as_bdd=False, rabin=False):
    """Add `"True"` to empty attributes `init`, `action`, `win`.

    @param as_bdd: if `True`, then represent `"True"` as `1`
    """
    if as_bdd:
        true = aut.bdd.true
        false = aut.bdd.false
    else:
        true = 'True'
        false = 'False'
    for d in (aut.init, aut.action):
        for k, v in d.items():
            if not v:
                d[k] = [true]
    if not aut.win['<>[]']:
        if rabin:
            aut.win['<>[]'] = [true]
        else:
            aut.win['<>[]'] = [false]
    if not aut.win['[]<>']:
        aut.win['[]<>'] = [true]
    for d in (aut.init, aut.action, aut.win):
        for k in d:
            assert len(d[k]) > 0
