In a single request to Azure Table Service, a maximum of 1000 entities will be returned (it could be anywhere from 0 to 1000). If there are more entities available, then Table Service will return you an opaque continuation token that you would need to use to fetch next set of entities.
What you need to do is fetch entities in an endless loop. In each iteration, you will pass your query and continuation token returned from previous request (you would pass null as continuation token for the 1st iteration). In result, you will get entities and optionally a continuation token (if more entities are available). You will continue this loop till the time you don't get back any continuation token.
Unfortunately I don't have Python environment setup, hence I can't show the code. However, I answered a similar question where I included code using .Net SDK. You can take a look at the code here: How to query all rows in windows azure table storage?. This should give you an idea about how you would accomplish the same in Python.