load-xls.py

import shutil, subprocess, tempfile, os
import openpyxl

def load_workbook_xls(filename, **kwargs):
    """Same as openpyxl.load_workbook, but supports XLS files instead of XLSX files."""
    soffice_path = shutil.which("soffice")
    if soffice_path is None:
        raise EnvironmentError("Can't find `soffice` executable - ensure Libreoffice Calc is installed correctly")

    with tempfile.TemporaryDirectory() as temp_xlsx_directory:
        subprocess.check_call([
            soffice_path, '--headless', '--convert-to', 'xlsx:Calc MS Excel 2007 XML', "--outdir", temp_xlsx_directory, os.path.realpath(filename)
        ], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL, cwd=temp_xlsx_directory)
        xlsx_file = os.listdir(temp_xlsx_directory)[0]
    return openpyxl.load_workbook(os.path.join(temp_xlsx_directory, xlsx_file), **kwargs)