code: def round(arg, digits=None):
      
      op = ops.Round(arg, digits)
      return op.to_expr()
docs: 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