scrapy/scrapy — pull request #986 by nyov (2014-12-16 19:21:12+00:00)
Title: Allow returning of None in CSVFeedSpider

to support ignoring rows (header/footer and such).

Example using CSVFeedSpider:
```py
def parse_row(self, response, row):
if row['COL1'] == 'FIRST-COLUMN':
self.log('Ignoring CSV header row')
return

[... continue here]
```

At this time, the Spider will barf when returning nothing/`None`.