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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def tokens2ids(tokens: Iterable[str], vocab: Dict[str, int]) -> List[int]: """ Returns sequence of integer ids given a sequence of tokens and vocab. :param tokens: List of string tokens. :param vocab: Vocabulary (containing UNK symbol). :return: List of word ids. """

    return [vocab.get(w, vocab[C.UNK_SYMBOL]) for w in tokens]