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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_row(self, obj):
 """ fill a new row with the given obj obj instance of the exporter's model """

        row = {}
        for column in self.headers:

            value = ''

            if '__col__' in column:
                if isinstance(column['__col__'], ColumnProperty):
                    value = self._get_column_cell_val(obj, column)

                elif isinstance(column['__col__'], RelationshipProperty):
                    value = self._get_relationship_cell_val(obj, column)

            row[column['name']] = value

        self._datas.append(self.format_row(row))