python类ColumnElement()的实例源码

def _get_col(self, row, key):
        if isinstance(key, schema.Column) or isinstance(key, sql.ColumnElement):
            try:
                rec = self.props[key._label.lower()]
            except KeyError:
                try:
                    rec = self.props[key.key.lower()]
                except KeyError:
                    rec = self.props[key.name.lower()]
        elif isinstance(key, str):
            rec = self.props[key.lower()]
        else:
            rec = self.props[key]
        return rec[0].convert_result_value(row[rec[1]], self.engine)