not working - python

import requests
import os

HEROKU_APP=os.environ['HEROKU_APP']
HEROKU_API_KEY=os.environ['HEROKU_API_KEY']

### scale up our application to 4 dynos
url     = 'https://api.heroku.com/apps/'+HEROKU_APP+'/formation'
head    = {"Content-Type": "application/json", "Accept": "application/vnd.heroku+json; version=3", "Authorization": "Bearer "+HEROKU_API_KEY}
payload = { "updates": [    {      "quantity": 4,      "type": "web"    }  ]}
r       = requests.patch(url,payload,headers=head)
print(r)

working - bash

curl -n -X PATCH https://api.heroku.com/apps/$HEROKU_APP/formation \
-d '{  "updates": [    {      "quantity": 4,      "type": "web"    }  ]}' \
-H 'Content-Type: application/json' \
-H "Accept: application/vnd.heroku+json; version=3"  \
-H "Authorization: Bearer $HEROKU_API_KEY"