Archive files directly from memory in Python

Question

I'm writing this program where I get a number of files, then zip them with encryption using pyzipper, and also I'm using io.BitesIO() to write these files to it so I keep them in-memory. So now, after some other additions, I want to get all of these in-memory files and zip them together in a single encrypted zip file using the same pyzipper.

The code looks something like this:

# Create the in-memory file object
in_memory = BytesIO()

# Create the zip file and open in write mode
with pyzipper.AESZipFile(in_memory, "w", compression=pyzipper.ZIP_LZMA, encryption=pyzipper.WZ_AES) as zip_file:

    # Set password
    zip_file.setpassword(b"password")

    # Save "data" with file_name
    zip_file.writestr(file_name, data)

# Go to the beginning
in_memory.seek(0)

# Read the zip file data
data = in_memory.read()

# Add the data to a list
files.append(data)

So, as you may guess the "files" list is an attribute from a class and the whole thing above is a function that does this a number of times and then you get the full files list. For simplicity's sake, I removed most of the irrelevant parts. I get no errors for now, but when I try to write all files to a new zip file I get an error. Here's the code:

with pyzipper.AESZipFile(test_name, "w", compression=pyzipper.ZIP_LZMA, encryption=pyzipper.WZ_AES) as zfile:
    zfile.setpassword(b"pass")
        for file in files:
            zfile.write(file)

I get a ValueError because of os.stat:

File "C:\Users\vulka\AppData\Local\Programs\Python\Python310\lib\site-packages\pyzipper\zipfile.py", line 820, in from_file
st = os.stat(filename)
ValueError: stat: embedded null character in path

[WHAT I TRIED]

So, I tried using mmap for this purpose but I don't think this can help me and if it can - then I have no idea how to make it work.

I also tried using fs.memoryfs.MemoryFS to temporarily create a virtual filessystem in memory to store all the files and then get them back to zip everything together and then save it to disk. Again - failed. I got tons of different errors in my tests and TBH, there's very little information out there on this fs method and even if what I'm trying to do is possible - I couldn't figure it out.

P.S: I don't know if pyzipper (almost 1:1 zipfile with the addition of encryption) supports nested zip files at all. This could be the problem I'm facing but if it doesn't I'm open to any suggestions for a new approach to doing this. Also, I don't want to rely on a 3rd party software, even if it is open source! (I'm talking about the method of using 7zip to do all the archiving and ecryption, even though it shouldn't even be possible to use it without saving the files to disk in the first place, which is the main thing I'm trying to avoid)