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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 vstack_empty(tup):
 """ A thin wrapper for numpy.vstack that ignores empty lists. Parameters tup: tuple or list of arrays with the same number of columns Returns stacked: (n,d) array, with same number of columns as constituent arrays. """

    # filter out empty arrays
    stackable = [i for i in tup if len(i) > 0]
    # if we only have one array just return it
    if len(stackable) == 1:
        return np.asanyarray(stackable[0])
    # if we have nothing return an empty numpy array
    elif len(stackable) == 0:
        return np.array([])
    # otherwise just use vstack as normal
    return np.vstack(stackable)