docs: def _remove_blacklisted(self, directories):
          """
          Attempts to remove the blacklisted directories from `directories`
          and then returns whatever is left in the set.
  
          Called from the `collect_directories` method.
          """
          directories = util.to_absolute_paths(directories)
          directories = util.remove_from_set(directories,
                                             self.blacklisted_directories)
  
          return directories