When creating hashed indexes, throws: TypeError: unsupported type for timedelta seconds component: str

File "build/bdist.macosx-10.4-x86_64/egg/pymongo/mongo_client.py", line 371, in _cache_index
expire = datetime.timedelta(seconds=cache_for) + now
TypeError: unsupported type for timedelta seconds component: str

Someone is throwing str for cache_for here. need to check datatype.

367 def _cache_index(self, database, collection, index, cache_for):
368 """Add an index to the index cache for ensure_index operations.
369 """
370 now = datetime.datetime.utcnow()
371 expire = datetime.timedelta(seconds=cache_for) + now