Updates the value of a cell.

        :param row: Row number.
        :type row: int
        :param col: Column number.
        :type col: int
        :param value: New value.

        Example::

            worksheet.update_cell(1, 1, '42')

def update_cell(self, row, col, value):
        """Updates the value of a cell.

        :param row: Row number.
        :type row: int
        :param col: Column number.
        :type col: int
        :param value: New value.

        Example::

            worksheet.update_cell(1, 1, '42')

        """
        range_label = '%s!%s' % (self.title, rowcol_to_a1(row, col))

        data = self.spreadsheet.values_update(
            range_label,
            params={
                'valueInputOption': 'USER_ENTERED'
            },
            body={
                'values': [[value]]
            }
        )

        return data