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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 add(self, col: str, value):
 """ Add a column with default values :param col: column name :type col: str :param value: column value :type value: any :example: ``ds.add("Col 4", 0)`` """

        try:
            self.df[col] = value
        except Exception as e:
            self.err(e, self.add, "Can not add column")