def counts(datalists, targets):
    """Returns: a new list where each element is how many elements of
    the corresponding list in datalists occur in targets.

    (Does not change datalists, any list in datalists, or targets.)

    Preconditions: Every element in datalists is a list of ints, possibly empty.
                   targets is a non-empty list of ints, no repeats.

    Example: If targets is [0, 12, -7, 13]
              and datalists is [[4000, 1100, 3600, 1000],
                                [12, -10000],
                                [13, 0, 13],
                                []]
              then the output is [0, 1, 3, 0]"""








