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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_level_lengths(levels, sentinel=''):
 """For each index in each level the function returns lengths of indexes. Parameters levels : list of lists List of values on for level. sentinel : string, optional Value which states that no new index starts on there. Returns Returns list of maps. For each level returns map of indexes (key is index in row and value is length of index). """

    if len(levels) == 0:
        return []

    control = [True] * len(levels[0])

    result = []
    for level in levels:
        last_index = 0

        lengths = {}
        for i, key in enumerate(level):
            if control[i] and key == sentinel:
                pass
            else:
                control[i] = False
                lengths[last_index] = i - last_index
                last_index = i

        lengths[last_index] = len(level) - last_index

        result.append(lengths)

    return result