localrepository: remove None as default value of path argument in __init__() The path variable in localrepository.__init__() has a default value None. So it gives us a option to create an object to localrespository class without path variable. But things break if you try to do so. The second line in the init which will be executed when we try to create a localrepository object will call os.path.expandvars(path) which returns TypeError: argument of type 'NoneType' is not iterable I checked occurrences when it is called and can't find any piece of code which calls it without path variable. Also if something is calling it, its should break.