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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 check_images(data):
 """ Check and reformat input images if needed """

    if isinstance(data, ndarray):
        data = fromarray(data)
    
    if not isinstance(data, Images):
        data = fromarray(asarray(data))

    if len(data.shape) not in set([3, 4]):
        raise Exception('Number of image dimensions %s must be 2 or 3' % (len(data.shape)))

    return data