Python Calls EXE from a different directory than the Python Script

I have a Python script that calls an EXE which in turns accesses and converts HTML/CSS/JS files to PDF. Importantly, all CSS and JS references in the HTML are relative paths as this script is expected to be accessed on different computers.

The Python script looks like this:

file_directory = os.path.realpath(os.path.dirname(__file__))

PATH_TO_EXE = os.path.join(file_directory, 'html-to-pdf.exe')

def convertHTML(*args):

    if not os.path.isfile(PATH_TO_EXE):
        raise FileNotFoundError("ERROR MESSAGE")

    call_args = f'\"{PATH_TO_EXE}\" \"' + '\" \"'.join(args) + '\"'
    subprocess.call(call_args)

The script is stored in a subdirectory of the root directory which is a GitHub repository.

If I run this script in VSCode by opening the subdirectory where the script is stored, everything works as intended, all CSS and JS is loaded since their relative paths are within the subdirectory.

However, if I am to open up the root directory in VSCode (which is normal for opening a GitHub repo) and run the script, the CSS and JS is not loaded because I suspect it is unable to find the CSS and JS because the HTML is now loaded in the root directory.

I imagine there is a way to work this out with the HTML, and certainly with the EXE (written in C#) to avoid this issue but I would rather deal with it in Python since that seems to be the inconsistency.

Can I either force the Python script to run within the same directory that it is stored or ensure it calls the function from the proper location?

I can run in the command line from any directory "C:/path/to/exe" "source.html" "output.pdf" and it WILL work properly since the HTML is loaded in the correct place.

Solution I worked out to ensure the correct directory is being used is to change to the directory of the file.

The code looks as follows:

# get file directory
file_directory = os.path.realpath(os.path.dirname(__file__))

# get path to exe
PATH_TO_EXE = os.path.join(file_directory, 'html-to-pdf.exe')

# change working directory if it is different than the file directory
if os.getcwd() != file_directory:
    os.chdir(file_directory)

def convertHTML(input, output):
    # check if the exe exists
    if not os.path.isfile(PATH_TO_EXE):
        raise FileNotFoundError("ERROR")

    # call the exe with the args
    subprocess.call([PATH_TO_EXE, input, output])


if __name__ == '__main__':
    convertHTML('source.html', 'output.pdf')