"libmat2.images.IOError: error while reading from input stream" on odp file

Hi,

mat2 0.10.0 (debian stable backports)

I can provide the specified file to a dev, privately. Of course mat2 works well on other odp files :)

mat2 file.odp

concurrent.futures.process._RemoteTraceback: 
"""
Traceback (most recent call last):
  File "/usr/lib/python3.7/concurrent/futures/process.py", line 232, in _process_worker
    r = call_item.fn(*call_item.args, **call_item.kwargs)
  File "/usr/bin/mat2", line 139, in clean_meta
    ret = p.remove_all()
  File "/usr/lib/python3/dist-packages/libmat2/archive.py", line 192, in remove_all
    member_parser, mtype = parser_factory.get_parser(full_path)  # type: ignore
  File "/usr/lib/python3/dist-packages/libmat2/parser_factory.py", line 57, in get_parser
    return parser_class(filename), mtype
  File "/usr/lib/python3/dist-packages/libmat2/images.py", line 65, in __init__
    cairo.ImageSurface.create_from_png(self.filename)
libmat2.images.cairo.IOError: error while reading from input stream

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3.7/concurrent/futures/process.py", line 198, in _sendback_result
    exception=exception))
  File "/usr/lib/python3.7/multiprocessing/queues.py", line 358, in put
    obj = _ForkingPickler.dumps(obj)
  File "/usr/lib/python3.7/multiprocessing/reduction.py", line 51, in dumps
    cls(buf, protocol).dump(obj)
_pickle.PicklingError: Can't pickle <class 'libmat2.images.cairo.IOError'>: attribute lookup cairo.IOError on libmat2.images failed
"""

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/usr/bin/mat2", line 228, in <module>
    sys.exit(main())
  File "/usr/bin/mat2", line 223, in main
    no_failure &= future.result()
  File "/usr/lib/python3.7/concurrent/futures/_base.py", line 425, in result
    return self.__get_result()
  File "/usr/lib/python3.7/concurrent/futures/_base.py", line 384, in __get_result
    raise self._exception
_pickle.PicklingError: Can't pickle <class 'libmat2.images.cairo.IOError'>: attribute lookup cairo.IOError on libmat2.images failed