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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 flat_(self, col, nums=True):
 """ Returns a flat representation of a column's values """

        try:
            res = ""
            i = 0
            vals = self.df[col].tolist()
            for el in vals:
                if nums is True:
                    res = res + str(i) + " " + el
                else:
                    res = res + el
                if i < (len(vals)-1):
                    res += " "
                i += 1
            return res
        except Exception as e:
            self.err(e, "Can not flat " + col)