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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 duplicated(values, keep='first'):
 """ Return boolean ndarray denoting duplicate values. .. versionadded:: 0.19.0 Parameters values : ndarray-like Array over which to check for duplicate values. keep : {'first', 'last', False}, default 'first' - ``first`` : Mark duplicates as ``True`` except for the first occurrence. - ``last`` : Mark duplicates as ``True`` except for the last occurrence. - False : Mark all duplicates as ``True``. Returns ------- duplicated : ndarray """


    values, dtype, ndtype = _ensure_data(values)
    f = getattr(htable, "duplicated_{dtype}".format(dtype=ndtype))
    return f(values, keep=keep)