Return a single cell's value

        :param obj obj: The instance we manage
        :param dict column: The column description dictionnary
        :returns: The associated value

def _get_column_value(self, obj, column):
        """
        Return a single cell's value

        :param obj obj: The instance we manage
        :param dict column: The column description dictionnary
        :returns: The associated value
        """
        return self._get_formatted_val(obj, column['__col__'].key, column)