Pip: install --find-links on multiple folder - pip

Question

I create a virtual environment with the command:
python -m venv ./my_venv
After activating this virtual env, I want to install some packages with .tar.gz archives.
My method to install my packages is explained in the following part:
PACKAGE1='/path/to/the/folder1'
PACKAGE2='/path/to/the/folder2'
PACKAGE3='/path/to/the/folder3'
PACKAGE4='/path/to/the/folder4'
pip install --find-links="${PACKAGE1}" package_1==1.0.0
pip install --find-links="${PACKAGE2}" package_2==1.0.0
pip install --find-links="${PACKAGE3}" package_3==1.0.0
pip install --find-links="${PACKAGE4}" package_4==1.0.0
Now I want to use a file requirements.txt like:
package_1==1.0.0
package_2==1.0.0
package_3==1.0.0
package_4==1.0.0
and run the command:
pip install --find-links="${PACKAGE}" -r requirements.txt
but
I don't find the way to tell pip to install using multiple folder.
Here is an example of what I want:
PACKAGE1='/path/to/the/folder1'
PACKAGE2='/path/to/the/folder2'
PACKAGE3='/path/to/the/folder3'
PACKAGE4='/path/to/the/folder4'
pip install --find-links="${PACKAGE1}" --find-links="${PACKAGE2}" --find-links="${PACKAGE3}" --find-links="${PACKAGE4}" -r requirements.txt
Obviously, I didn't work.
Can you help me ? :)

Answer 1

Have a look at the --find-links documentation again:
If a local path ... that’s a directory, then look for archives in the directory listing.
So /path/to/the/folder4 for example will need to contain an archive/wheel for package4. This will not work if /path/to/the/folder4 is just the source directory/root for package4.