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: cleaner.rb
    path of file: ./repos/squasher/lib/squasher
    
    the code of the file until where you have to start completion: require 'fileutils'

module Squasher
  class Cleaner
    MIGRATION_NAME = 'squasher_clean'

    de
    
    def process
      Squasher.error(:migration_folder_missing) unless config.migrations_folder?

      migration_file = config.migration_file(now_timestamp, MIGRATION_NAME)
      if prev_migration
        FileUtils.rm(prev_migration)
      end