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: 20150203151605_cleanup_old_fields.rb
    path of file: ./repos/Autolab/db/migrate
    
    the code of the file until where you have to start completion: class CleanupOldFields < ActiveRecord::Migration[4.2]
  def change

    remove_column :assessments, :late_penalty_old, :float
    remove_column :assessments, :version_penalty_old, :float

    remove_column :attachments, :type_old, :string
    remove_column :attachments, :foreign_key_old, :integer

    remove_column :course_user_data, :tweak_old, :float
    remove_column :course_user_data, :absolute_tweak, :boolean
    remove_column :course_user_data, :first_name_backup, :string
    remove_column :course_user_data, :last_name_backup, :string
    remove_column :course_user_data, :andrewID_backup, :string
    rem
    
  def change

    remove_column :assessments, :late_penalty_old, :float
    remove_column :assessments, :version_penalty_old, :float

    remove_column :attachments, :type_old, :string
    remove_column :attachments, :foreign_key_old, :integer

    remove_column :course_user_data, :tweak_old, :float
    remove_column :course_user_data, :absolute_tweak, :boolean
    remove_column :course_user_data, :first_name_backup, :string
    remove_column :course_user_data, :last_name_backup, :string
    remove_column :course_user_data, :andrewID_backup, :string
    remove_column :course_user_data, :school_backup, :string
    remove_column :course_user_data, :major_backup, :string
    remove_column :course_user_data, :year_backup, :string
    remove_column :course_user_data, :email_backup, :string
    remove_column :course_user_data, :administrator_backup, :boolean


    remove_column :courses, :late_penalty_old, :float
    remove_column :courses, :version_penalty_old, :float

    if column_exists? :submissions, :tweak_old
        remove_column :submissions, :tweak_old, :float
    end