How to diagnose a Django site not working problem?

Question

Django

There is a site that works this way if left untouched, but sometimes it can stop working on its own, for example after restarting the server or after the moon phase does not converge with the Django phase.
At the moment, any attempt to call any ./manage.py command gives me the following error:

Traceback (most recent call last):
  File "./manage.py", line 8, in <module>
    from django.core.management import execute_from_command_line
  File "/home/profograd_ru/profograd_ru/django/__init__.py", line 1, in <module>
    from django.utils.version import get_version
  File "/home/profograd_ru/profograd_ru/django/utils/version.py", line 7, in <module>
    from django.utils.lru_cache import lru_cache
  File "/home/profograd_ru/profograd_ru/django/utils/lru_cache.py", line 28
    fasttypes = {int, str, frozenset, type(None)},
                    ^
SyntaxError: invalid syntax

The same is issued when running this script without arguments.
Tell me what to do with it? How to identify the problem? Which tambourine should be played?

Answer 1

Use Python version 2.7 and up.