Pylons/pyramid — pull request #680 by mitchellrj (2012-09-04 11:11:18+00:00)
Title: Handle the case where an empty range is requested

If a client makes a request to a static resource with a range header (for example) of 400-400 (valid HTTP), this iterator will fail at this point. It is better to check the block size here, as we would still want to raise other errors at this point.