AttributeError: module 'posixpath' has no attribute 'sep' in pycharm

Traceback (most recent call last):
  File "/home/varshini/CAV-Assessment/venv/lib/python3.10/site-packages/flask/app.py", line 2073, in wsgi_app
    response = self.full_dispatch_request()
  File "/home/varshini/CAV-Assessment/venv/lib/python3.10/site-packages/flask/app.py", line 1519, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/home/varshini/CAV-Assessment/venv/lib/python3.10/site-packages/flask/app.py", line 1517, in full_dispatch_request
    rv = self.dispatch_request()
  File "/home/varshini/CAV-Assessment/venv/lib/python3.10/site-packages/flask/app.py", line 1503, in dispatch_request
    return self.ensure_sync(self.view_functions[rule.endpoint])(**req.view_args)
  File "/home/varshini/CAV-Assessment/src/cav/api/WebApp.py", line 71, in index
    return render_template('index.html')
  File "/home/varshini/CAV-Assessment/venv/lib/python3.10/site-packages/flask/templating.py", line 155, in render_template
    ctx.app.jinja_env.get_or_select_template(template_name_or_list),
  File "/home/varshini/CAV-Assessment/venv/lib/python3.10/site-packages/jinja2/environment.py", line 1081, in get_or_select_template
    return self.get_template(template_name_or_list, parent, globals)
  File "/home/varshini/CAV-Assessment/venv/lib/python3.10/site-packages/jinja2/environment.py", line 1010, in get_template
    return self._load_template(name, globals)
  File "/home/varshini/CAV-Assessment/venv/lib/python3.10/site-packages/jinja2/environment.py", line 969, in _load_template
    template = self.loader.load(self, name, self.make_globals(globals))
  File "/home/varshini/CAV-Assessment/venv/lib/python3.10/site-packages/jinja2/loaders.py", line 126, in load
    source, filename, uptodate = self.get_source(environment, name)
  File "/home/varshini/CAV-Assessment/venv/lib/python3.10/site-packages/flask/templating.py", line 59, in get_source
    return self._get_source_fast(environment, template)
  File "/home/varshini/CAV-Assessment/venv/lib/python3.10/site-packages/flask/templating.py", line 92, in _get_source_fast
    return loader.get_source(environment, template)
  File "/home/varshini/CAV-Assessment/venv/lib/python3.10/site-packages/jinja2/loaders.py", line 195, in get_source
    pieces = split_template_path(template)
  File "/home/varshini/CAV-Assessment/venv/lib/python3.10/site-packages/jinja2/loaders.py", line 32, in split_template_path
    os.path.sep in piece
AttributeError: module 'posixpath' has no attribute 'sep'