Yep, I'm not noticed what `os` not imported.
After import:
Runspider
```
~/dev/spider/pws/spiders ❯ ~/dev/scrapy/bin/scrapy runspider pws_spider.py -o ./data.                                                 
Usage
=====
  scrapy runspider [options] <spider_file>

runspider: error: Invalid/unrecognized output format: , Expected ['xml', 'jsonlines', 'json', 'csv', 'pickle', 'marshal']
```
Crawl:
```
~/dev/spider/pws/spiders ❯ ~/dev/scrapy/bin/scrapy crawl pws_spider.py -o ./data.                                                    
Usage
=====
  scrapy crawl [options] <spider>

crawl: error: Invalid/unrecognized output format: , Expected ['xml', 'jsonlines', 'json', 'csv', 'pickle', 'marshal']
```