[Python] How to sort files inside a directory to follow order by file size?

I have a directory in which I have 3 files, 2 being directories and another which is a mimetype. I want to keep the mimetype as the first file in the directory, so I made the mimetype first inside the directory. But when I transform that directory into an archive with shutil.make_archive() the resulting archive has the mimetype at the bottom of the directory. Any way to sort the files before using shutil.make_archive() so that the mimetype doesn't end up at the bottom of the directory?

Code currently looks like this:

os.makedires("mainDirectory")
os.chdir("mainDirectory")

file = open("mimetype", "w", encoding="ASCII")
file.write("...")

os.makedirs("directory1")
os.makedirs("directory2")
os.chdir("directory1")
... #changes to directory 1

os.chdir("directory2")
... #changes to directory 2

os.chdir("mainDirectory")
make_archive("mainDirectory", "zip", "mainDirectory")

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