docs: def migrations_to_run(self):
          """
          Get a list of migrations to run still, if any.
  
          Note that this will fail if there's no migration record for
          this class!
          """
          assert self.database_current_migration is not None
  
          db_current_migration = self.database_current_migration
  
          return [
              (migration_number, migration_func)
              for migration_number, migration_func in self.sorted_migrations
              if migration_number > db_current_migration]