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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 round(arg, digits=None):
 """ Round values either to integer or indicated number of decimal places. Returns ------- rounded : type depending on digits argument digits None or 0 decimal types: decimal other numeric types: bigint digits nonzero decimal types: decimal other numeric types: double """

    op = ops.Round(arg, digits)
    return op.to_expr()