How to install packages from given wheel files?

I am preparing a python zip file in ADO, then send it to Azure for deployment/build. I have python packages in a private azure feed, so I download them and include in the zip archive. What I then would like to do is to run the command like this python -m pip install -r requirements.txt --no-index --find-links ./bins. I tried to set PRE_BUILD_COMMAND=python -m pip install -r requirements.txt --no-index --find-links ./bins, but this results in error:

Oryx Version: 0.2.20250522.1+cada9e85564f034d18420f8b5b38b3cf2259f321, Commit: cada9e85564f034d18420f8b5b38b3cf2259f321, ReleaseTagName: 20250522.1

Build Operation ID: 19a0b713b5da23c5
Repository Commit : 10e40993-765b-43ce-9bdb-0cd5b871e6c7
OS Type           : buster
Image Type        : githubactions

Primary SDK Storage URL: https://oryxsdks-cdn.azureedge.net/
Backup SDK Storage URL: https://oryx-cdn.microsoft.io/
Detecting platforms...
Detected following platforms:
  python: 3.9.22
Version '3.9.22' of platform 'python' is not installed. Generating script to install it...

Using intermediate directory '/tmp/8dda357aabb0c84'.

Copying files to the intermediate directory...
Done in 1 sec(s).

Source directory     : /tmp/8dda357aabb0c84
Destination directory: /home/site/wwwroot


Downloading and extracting 'python' version '3.9.22' to '/tmp/oryx/platforms/python/3.9.22'...
Detected image debian flavor: buster.
Downloaded in 5 sec(s).
Verifying checksum...
Extracting contents...
performing sha512 checksum for: python...
Done in 21 sec(s).

Executing pre-build command...
/usr/bin/python: No module named pip
/usr/bin/python: No module named pip\n/bin/bash -c "oryx build /tmp/zipdeploy/extracted -o /home/site/wwwroot --platform python --platform-version 3.9 -p virtualenv_name=antenv --log-file /tmp/build-debug.log  -i /tmp/8dda357aabb0c84 --compress-destination-dir | tee /tmp/oryx-build.log ; exit $PIPESTATUS "

How to do this? Or should I issue it as part of the post_build command?

Start with the reported PRE_BUILD_COMMAND and the Oryx build log, especially the Python 3.9.22 setup and the “No module named pip” error. Clarify whether local wheel installation is expected during pre-build or post-build; done means documenting or supporting a working path for installing requirements from ./bins.