tomchristie/django-rest-framework — pull request #632 by fernandogrd (2013-01-29 21:58:46+00:00)
Title: Fix processing of ManyToManyField when it is empty 

If data does not contain the ManyToManyField or it is empty, the first try fails, because dict does not have getlist attribute.
Then, in except clause, value receives None, because it can't find field_name in data.

We then get: TypeError: 'NoneType' object is not iterable
When it tries to iterate over None value.