TypeError: 'NoneType' object is not iterable #19

reloading plugin Gitignored File Excluder.gitignore_plugin
Traceback (most recent call last):
File "C:\Program Files\Sublime Text 3\sublime_plugin.py", line 78, in reload_plugin
m = importlib.import_module(modulename)
File "./importlib/init.py", line 90, in import_module
File "", line 1584, in _gcd_import
File "", line 1565, in _find_and_load
File "", line 1532, in _find_and_load_unlocked
File "C:\Program Files\Sublime Text 3\sublime_plugin.py", line 696, in load_module
exec(compile(source, source_path, 'exec'), mod.dict)
File "gitignore_plugin in C:\Users\craig\AppData\Roaming\Sublime Text 3\Installed Packages\Gitignored File Excluder.sublime-package", line 229, in
File "gitignore_plugin in C:\Users\craig\AppData\Roaming\Sublime Text 3\Installed Packages\Gitignored File Excluder.sublime-package", line 35, in start
File "gitignore_plugin in C:\Users\craig\AppData\Roaming\Sublime Text 3\Installed Packages\Gitignored File Excluder.sublime-package", line 32, in run
File "gitignore_plugin in C:\Users\craig\AppData\Roaming\Sublime Text 3\Installed Packages\Gitignored File Excluder.sublime-package", line 65, in update_file_exclude_patterns
TypeError: 'NoneType' object is not iterable