| Switch to a new parser, based on PEG. For more details see PEP 617. To | |
| temporarily switch back to the old parser, use ``-X oldparser`` or | |
| ``PYTHONOLDPARSER=1``. In Python 3.10 we will remove the old parser | |
| completely, including the ``parser`` module (already deprecated) and | |
| anything that depends on it. |