delendent dropdown in django(DJango,Python)
One of approach you can take is :

User go to page
Back End get the list of country and pass it to front end
User select 1 country from drop-down
Front end java-script use ajax call to pass country to back-end and get all states
Front end show all states in second drop-down
User select 1 state from drop-down 
Front end java-script use ajax call to pass state to back-end and get all district
Front end show all district in third drop-down

but this kind of slow, so choose wisly
I want to make four drop down button(like country state city and location)each field we want to make it based on the selection like when country select its state related to country we get and when state is s selected then city related to these state gets populated when city get slelected then its loctation related to these city we get