[QUESTION] Title Google play books dedrm doesn't work

CheckList

[ ] The Title and The Log Title are setted correctly.
[ ] Clarified about my environment.
[ ] Code block is used for the log.

Title

My Environment

Calibre: `5.33`

Kindle: `Version`

DeDRM: `7.2.1`

Log

Log Title

```log calibre, version 5.33.0 ERROR: Loading book failed: Failed to open the book at C:\Users\****\Calibre Library\San Dao Yu Meng\Yi Nu geShi Jie hamobuniYan siiShi J (3)\metadata.opf. Click "Show details" for more info. Failed to convert book: C:\Users\****\Calibre Library\San Dao Yu Meng\Yi Nu geShi Jie hamobuniYan siiShi J (3)\metadata.opf with error: InputFormatPlugin: HTML Input running on C:\Users\****\Calibre Library\San Dao Yu Meng\Yi Nu geShi Jie hamobuniYan siiShi J (3)\metadata.opf Parsing all content... Failed to run pipe worker with command: from calibre.srv.render_book import viewer_main; viewer_main() Traceback (most recent call last): File "runpy.py", line 194, in _run_module_as_main File "runpy.py", line 87, in _run_code File "site.py", line 82, in File "site.py", line 77, in main File "site.py", line 49, in run_entry_point File "calibre\utils\ipc\worker.py", line 197, in main File "", line 1, in File "calibre\srv\render_book.py", line 824, in viewer_main File "calibre\srv\render_book.py", line 815, in render_for_viewer File "calibre\srv\render_book.py", line 792, in render File "calibre\ebooks\oeb\iterator\book.py", line 63, in extract_book File "calibre\customize\conversion.py", line 244, in __call__ File "calibre\ebooks\conversion\plugins\html_input.py", line 95, in convert File "calibre\ebooks\conversion\plumber.py", line 1326, in create_oebbook File "calibre\ebooks\oeb\reader.py", line 71, in __call__ File "calibre\ebooks\oeb\reader.py", line 698, in _all_from_opf File "calibre\ebooks\oeb\reader.py", line 343, in _spine_from_opf calibre.ebooks.oeb.base.OEBError: Spine is empty ```

apprenticeharper / DeDRM_tools