'Queues events for directory modifications by scanning the directory
for changes.
A scan is a comparison between two snapshots of the same directory
taken at two different times. This also determines whether files
or directories were created, which updated the modified timestamp
for the directory.'

def _queue_dirs_modified(self, dirs_modified, ref_snapshot, new_snapshot):

    if dirs_modified:
        for dir_modified in dirs_modified:
            self.queue_event(DirModifiedEvent(dir_modified))
        diff_events = (new_snapshot - ref_snapshot)
        for file_created in diff_events.files_created:
            self.queue_event(FileCreatedEvent(file_created))
        for directory_created in diff_events.dirs_created:
            self.queue_event(DirCreatedEvent(directory_created))
