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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 isin(arg, values):
 """ Check whether the value expression is contained within the indicated list of values. Parameters values : list, tuple, or array expression The values can be scalar or array-like. Each of them must be comparable with the calling expression, or None (NULL). Examples -------- Returns ------- contains : BooleanValue """

    op = ops.Contains(arg, values)
    return op.to_expr()