I’m not too familiar with Python, but if you are trying to get a total count of 1500 keywords for a single day, you could use the following:
curl -X POST "https://api.twitter.com/1.1/tweets/search/30day/dev0/counts.json" -d '{"query":"keyword1 OR keyword2 OR keyword3 OR ...","fromDate":"201808080000","toDate":"201808090000","bucket":"day"}' -H "Authorization: Bearer TOKEN"
Making sure to replace TOKEN with your bearer token and replacing the keyword1, 2, 3 with your keywords.
If you need to get the counts for each of those keywords separately, then you can just run the query with a single keyword and rerun the request for each of your keywords.
I’ll see if I can point someone your way to help with the python query.