Python: “List.append = ‘list’ object attribute ‘append’ is read-only”

>>> list.append
<method 'append' of 'list' objects>

You're trying to modify the append method of the built-in list class!

Just do

docstats = []
for doc in response.results:
    docstats.append(json.loads(doc['status']))

or equivalently:

docstats = [json.loads(doc['status']) for doc in response.results]