I'm migrating data from erp 7 to Odoo 13. I've written migration scripts myself (on Postgres). However after migration runs, I keep getting this error 

psycopg2.ProgrammingError: column "type" of relation "ir_actions_todo" does not exist

when I try updating my module. 

The error stems from this line:
cr.execute('ALTER TABLE "{}" ALTER COLUMN "{}" DROP NOT NULL'.format(tablename, columnname))

And so my question becomes: Why was the type field deprecated in ir_actions_todo?