Developer mode - changes not reflecting

I am using version 12
Once i write the python code then i need stop bench and start bench to see the chnages.
i have change the site.json with

“db_name”: “*************”,
“db_password”: “***********”,
“db_type”: “mariadb”,
“developer_mode”: 1
also execute the command on bench :
bench set-config developer_mode 1
However still i need to stop start bench each time
using bench migrate and bench restart python changes do not reflect
Please help