I just installed django and after installing that I created a django project and was trying to run django server by command:
python manage.py runserver
Just open file: venv/lib/python3.7/site-packages/django/contrib/admin/widgets.py and replace the lines
venv/lib/python3.7/site-packages/django/contrib/admin/widgets.py
related_url += '?' + '&'.join( '%s=%s' % (k, v) for k, v in params.items(),)
with
related_url += '?' + '&'.join('%s=%s' % (k, v) for k, v in params.items())