TypeError: 'type' object is not subscriptable while Starting Backend

I am initializing azure-search-openai-demo project locally using ./start.sh command and here is the error I am getting from app.py. Here is the error log below:

Building frontend


> frontend@0.0.0 build
> tsc && vite build

vite v4.1.1 building for production...
✓ 1250 modules transformed.
../backend/static/index.html                    0.47 kB
../backend/static/assets/github-fab00c2d.svg    0.96 kB
../backend/static/assets/index-2fb53ec2.css     7.44 kB │ gzip:   2.19 kB
../backend/static/assets/index-7abdfda7.js    625.74 kB │ gzip: 204.86 kB │ map: 5,054.95 kB

(!) Some chunks are larger than 500 kBs after minification. Consider:
- Using dynamic import() to code-split the application
- Use build.rollupOptions.output.manualChunks to improve chunking: https://rollupjs.org/configuration-options/#output-manualchunks
- Adjust chunk size limit for this warning via build.chunkSizeWarningLimit.

Starting backend

Traceback (most recent call last):
  File "./app.py", line 12, in <module>
    from approaches.chatreadretrieveread import ChatReadRetrieveReadApproach
  File "/home/milin/azure-search-openai-demo/app/backend/approaches/chatreadretrieveread.py", line 10, in <module>
    class ChatReadRetrieveReadApproach(Approach):
  File "/home/milin/azure-search-openai-demo/app/backend/approaches/chatreadretrieveread.py", line 51, in ChatReadRetrieveReadApproach
    def run(self, history: list[dict], overrides: dict) -> any:
TypeError: 'type' object is not subscriptable
Failed to start backend