error on catalina when scanning photographs

[lawzeus]

Describe the bug
A clear and concise description of what the bug is.

To Reproduce
Steps to reproduce the behavior:

1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error

Expected behavior
A clear and concise description of what you expected to happen.

Screenshots
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Desktop (please complete the following information):

• OS: [e.g. Windows 10 / OSX 10.15 / Ubuntu 20.04]
• Version [e.g. 4.0.4]

Additional context
Application Identifier: com.hardcoded-software.dupeguru
Application Version: 4.0.3
Mac OS X Version: Version 10.15.7 (Build 19H2)

Traceback (most recent call last):
File "build/dupeGuru.app/Contents/Resources/py/cocoa/inter.py", line 259, in pulse
File "build/dupeGuru.app/Contents/Resources/py/hscommon/gui/progress_window.py", line 101, in pulse
a File "build/dupeGuru.app/Contents/Resources/py/hscommon/jobprogress/performer.py", line 43, in _async_run
File "build/dupeGuru.app/Contents/Resources/py/core/app.py", line 780, in do
File "build/dupeGuru.app/Contents/Resources/py/core/scanner.py", line 137, in get_dupe_groups
File "build/dupeGuru.app/Contents/Resources/py/core/pe/scanner.py", line 31, in _getmatches
File "build/dupeGuru.app/Contents/Resources/py/core/pe/matchblock.py", line 167, in getmatches
File "build/dupeGuru.app/Contents/Resources/py/core/pe/matchblock.py", line 65, in prepare_pictures
File "build/dupeGuru.app/Contents/Resources/py/core/pe/cache_shelve.py", line 129, in purge_outdated
File "build/dupeGuru.app/Contents/Resources/py/core/pe/cache_shelve.py", line 47, in delitem
File "build/dupeGuru.app/Contents/Resources/py/shelve.py", line 128, in __delitem__KeyError: b'id:31673'

[glubsy]

This has been reported many times already, and is supposedly fixed in version 4.0.4. Unfortunately there is no package for MacOS right now, so you'll have to build and install from this git repository to fix the problem.

[arsenetar]

Duplicate of #439