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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 _array_or_placeholder( maybe_iterable, placeholder=PLACEHOLDER_ZEROS ) -> np.array: """ Return maybe_iterable's contents or a placeholder array. Used to give bqplot its required initial points to plot even if we're using a function to generate points. """

    if isinstance(maybe_iterable, collections.Iterable):
        return np.array([i for i in maybe_iterable])
    return placeholder