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: 20171107165145_add_new_events_and_fields_to_balance_transactions.rb
    path of file: ./repos/catarse/db/migrate
    
    the code of the file until where you have to start completion: class AddNe
    
  def down
    remove_column :balance_transactions, :subscription_payment_id
    execute %Q{
    drop index if exists balance_subscription_payment_evt_uniq;
    drop index if exists balance_subscription_fee_evt_uniq;
}
  end