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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 unique_(self, col):
 """ Returns unique values in a column """

        try:
            df = self.df.drop_duplicates(subset=[col], inplace=False)
            return list(df[col])
        except Exception as e:
            self.err(e, "Can not select unique data")