pipreqs not capturing all imports

In my code I wanted to create a requirements.txt file with all the dependencies needed to run my model.
I used pip freeze earlier, however, because of obvious reasons i.e. it captures everything from the environment and not just the ones needed for my model, I moved to pipreqs.

I tested it with a very basic .py file with some imports, out of those the following is not getting captured correctly:
`import cv2`

The problem I faces is:
It fails to capture opencv-python for cv2.

Below error is thrown:
DEBUG: Starting new HTTPS connection (1): pypi.org
DEBUG: https://pypi.org:443 "GET /cv2/json HTTP/1.1" 404 1443
DEBUG: Package cv2 does not exist or network problems

Can anyone help here.

Start by reproducing the issue with a basic .py file containing `import cv2`, then inspect how pipreqs resolves imports before its PyPI lookup. The work is done when the generated requirements.txt includes `opencv-python` for that import and the cv2 lookup error no longer occurs.

Written by the indexing model from the issue text.