why .my python 3.9

error: subprocess-exited-with-error

× Preparing metadata (pyproject.toml) did not run successfully.

To solve this error try to download the source code of the required package which will be available on GitHub otherwise in the official website of that package and then try to install the package from the command prompt

@johnsmith111333 This issue is with the preparation of the metadata for one or more of the packages listed in the requirements.txt file. This could be due to a variety of reasons, including missing dependencies, compatibility issues, or problems with the pyproject.toml file.
Try out these steps and let me know, if it works:

1. Ensure Up-to-Date pip and setuptools by making sure you have the latest versions of pip and setuptools.
2. use a Virtual env for avoiding package conflicts while installing.
3. Some packages might use pyproject.toml for their build system. Ensure that the required build tools are installed through
   pip install build

let me know if this solves your issue
Thanks