Sequel generate migration

cp_generate_migration.rake

namespace :generate do
  desc 'Generate a timestamped, empty Sequel migration.'
  task :migration, :name do |_, args|
    if args[:name].nil?
      puts 'You must specify a migration name (e.g. rake generate:migration[create_contacts])!'
      exit false
    end

    content = "Sequel.migration do\n  up do\n    \n  end\n\n  down do\n    \n  end\nend\n"
    seq_next = get_next_seq
    filename = File.join(File.dirname(__FILE__), 'migrations', "#{seq_next}_#{args[:name]}.rb")

    File.open(filename, 'w') do |f|
      f.puts content
    end

    puts "Created the migration #{filename}"
  end
end

is there a get_next_seq method somewhere?