Use of len(seq) - 1 to get last element of an iterable PTC-W0044
There’s no need to calculate length of an iterable in order to fetch the last element of the iterable. You can provide a negative index -1 to it directly in orger to get the last element. In this way, you don't have to iterate over the sequence using len to get the last index when your purpose is only to get the last element.
Consider decorating method with @staticmethod PYL-R0201
The method doesn't use its bound instance. Decorate this method with @staticmethod decorator, so that Python does not have to instantiate a bound method for every instance of this class thereby saving memory and computation. Read more about staticmethods here.
New column added in database with a default value PYL-W5198
The preferred way is to add a new DB column with null=True because it will be created instantly and then possibly populate the table with the desired default values. Adding a default value will lead to a performance issue if the existing table has a large number of rows.
Expression not assigned PYL-W0106
An expression that is not a function call is assigned to nothing. Probably something else was intended here. We recommend to review this.
Consider using literal syntax to create the data structure PTC-W0019
Using the literal syntax can give minor performance bumps compared to using function calls to create dict, list and tuple.