You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: 20131201172300_assignments_add_columns.rb
    path of file: ./repos/expertiza/db/migrate
    
    the code of the file until where you have to start completion: class AssignmentsAddColumns < ActiveRecord::Migration[4.2]

  def self.up
    add_column :ass
    
  def self.down
    execute 'ALTER TABLE assignments DROP FOREIGN KEY `fk_late_policy_id`;'

    remove_column :assignments, :calculate_penalty
    remove_column :assignments, :late_policy_id
    remove_column :assignments, :is_penalty_calculated
  end