How does one get a count of rows in a Datastore model in Google App Engine?

Question

I need to get a count of records for a particular model on App Engine. How does one do it?

I bulk uploaded more than 4000 records but modelname.count() only shows me

Answer 1

count = modelname.all(keys_only=True).count(some_upper_limit)

Just to add on to the earlier post by dar, this 'some_upper_limit' has to be specified. If not, the default count will still be a maximum of 1000.