Dirsearch will fail when discovering new path with switch --crawl enabled. #1576

What is the current behavior?

What actually happens?
dirsearch would throws exception at file lib/controller/controller.py line 589 when discovering new path with --crawl switch on.

What is the expected behavior?

What it should be instead?
dirsearch should add the crawled path into scan queue

Any additional information?

looks like it's caused by commit 27ed360 , which removes method is_valid from the Dictionary class while splitting backend implementation from it.

Screenshots, dirsearch log, dirsearch version, used command, ...?
dirsearch version: 06c1be6