Django KeyError when starting - django

Question

I accidentally pulled an old git repo of my Django build ( It's running on a Heroku dyno ) and it had overwritten my entire local build, I managed to restore it back to the latest git repo which was previously working on my local build ( but not my Heroku dyno ) and the server now won't run locally or on my live build?
Error from the shell:
python manage.py runserver
File "manage.py", line 22, in <module>
execute_from_command_line(sys.argv)
File "/home/johnnie/.local/lib/python3.7/site-packages/django/core/management/__init__.py", line 401, in execute_from_command_line
utility.execute()
File "/home/johnnie/.local/lib/python3.7/site-packages/django/core/management/__init__.py", line 345, in execute
settings.INSTALLED_APPS
File "/home/johnnie/.local/lib/python3.7/site-packages/django/conf/__init__.py", line 76, in __getattr__
self._setup(name)
File "/home/johnnie/.local/lib/python3.7/site-packages/django/conf/__init__.py", line 63, in _setup
self._wrapped = Settings(settings_module)
File "/home/johnnie/.local/lib/python3.7/site-packages/django/conf/__init__.py", line 142, in __init__
mod = importlib.import_module(self.SETTINGS_MODULE)
File "/usr/lib/python3.7/importlib/__init__.py", line 127, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File "<frozen importlib._bootstrap>", line 1006, in _gcd_import
File "<frozen importlib._bootstrap>", line 983, in _find_and_load
File "<frozen importlib._bootstrap>", line 967, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 677, in _load_unlocked
File "<frozen importlib._bootstrap_external>", line 728, in exec_module
File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
File "/home/johnnie/myproject/myproject/mysite/mysite/settings.py", line 141, in <module>
del DATABASES['default']['OPTIONS']['sslmode']
KeyError: 'OPTIONS'
edit:
del DATABASES['default']['OPTIONS']['sslmode']
was a section added by Heroku when committed by git.
removed this plus other Heroku changes which resolved issues.