state, Alphabet alpha)
                 => NFA state alpha -> state -> Bool
isAcceptState nfa s = S.member s $ nfaAccepts nfa

-- デフォルト付き lookup
look
isAcceptState :: (State state, Alphabet alpha)
                 => NFA state alpha -> state -> Bool
isAcceptState nfa s = S.member s $ nfaAccepts nfa
isAcceptState nfa s = S.member s $ nfaAccepts nfa