how to update a non updatable view?

I'm working on odoo version11. I created a view named test. I upgraded the module. Later I need to make some changes including changing some values and removing some values. Whenever I try to upgrade the module I get the error

psycopg2.OperationalError: cannot delete from view "test" DETAIL: Views containing GROUP BY are not automatically updatable. HINT: To enable deleting from the view, provide an INSTEAD OF DELETE trigger or an unconditional ON DELETE DO INSTEAD rule.

How to provide the rule? My code is as follows

@api.model_cr
def init(self):
    cr = self.env.cr   
    tools.drop_view_if_exists(cr, 'o_test')
    cr.execute("""
    
                CREATE or replace view o_test as 
                (
                    SELECT 
                        mve.id as id,
                        acc.code as account_code,
                        SUM (mve.debit-mve.credit) AS balance,
                        mve.account_id as account_id
                    FROM account_move_line mve
                    LEFT JOIN account_account acc ON mve.account_id = acc.id 
                    GROUP BY mve.id,mve.account_id,acc.code
                )
            """)

I want to change the code to as follows:

@api.model_cr
def init(self):
    cr = self.env.cr   
    tools.drop_view_if_exists(cr, 'o_test')
    cr.execute("""
    
                CREATE or replace view o_test as 
                (
                    SELECT 
                        mve.account_id as id,
                        acc.code as account_code,
                        SUM (mve.debit-mve.credit) AS balance,
                        mve.account_id as account_id
                    FROM account_move_line mve
                    LEFT JOIN account_account acc ON mve.account_id = acc.id 
                    GROUP BY mve.account_id,acc.code
                )
            """)

Editable Views can be created in Postgres using Rules and GROUP BY clause should not be a problem. You can write rule like the below for update query. Here I have updated only one column

CREATE OR REPLACE RULE update_o_test AS
    ON UPDATE TO o_test
    DO INSTEAD
 UPDATE account_account SET code = new.code
  WHERE account_account.id = old.id;

Similarly you can create rules for Insert and Delete operations. Adding rules after the end of your create view statement should work. Hope this helps...