can you please help me with some code how to do implement these required tasks please?

(a) Any record associated with an unknown cell in work-class should be removed from the dataset. (b) Some values in Age columns are represented as decade, e.g., 20s or 30s. You are required to clean these values by removing the s and convert it into an integer value. (c) Income is either less or equal than 50k or greater than 50k. (d) Cross validation using 5 folds and 20% test size.