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: 20170920024819_status_ids_to_timestamp_ids.rb
    path of file: ./repos/mastodon/db/migrate
    
    the code of the file until where you have to start completion: # frozen_
    
  def up
    # Prepare the function we will use to generate IDs.
    Mastodon::Snowflake.define_timestamp_id

    # Set up the statuses.id column to use our timestamp-based IDs.
    ActiveRecord::Base.connection.execute(<<~SQL.squish)
      ALTER TABLE statuses
      ALTER COLUMN id
      SET DEFAULT timestamp_id('statuses')
    SQL

    # Make sure we have a sequence to use.
    Mastodon::Snowflake.ensure_id_sequences_exist
  end