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)``

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")