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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 unique_by_index(sequence):
 """ unique elements in `sequence` in the order in which they occur Parameters sequence : iterable Returns ------- uniques : list unique elements of sequence, ordered by the order in which the element occurs in `sequence` """

    uniques = []
    for element in sequence:
        if element not in uniques:
            uniques.append(element)
    return uniques