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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 get_analogy_task_tokens(args):
 """Returns a set of all tokens occuring the evaluation datasets."""

    tokens = set()
    for _, _, dataset in iterate_analogy_datasets(args):
        tokens.update(
            itertools.chain.from_iterable(
                (d[0], d[1], d[2], d[3]) for d in dataset))
    return tokens