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: infrequency_tracking_notifier.rb
    path of file: ./repos/i-diario/app/services
    
    the code of the file until where you have to start completion: class InfrequencyTrackingNotifier
  def self.notify!
    new.notify!
  end

  def notify!
    retur
    
  def students_with_absences_query(start_at = nil)
    start_at ||= Date.current.beginning_of_year

    UniqueDailyFrequencyStudent.frequency_date_between(start_at, end_at)
                               .where(present: false)
                               .includes(:classroom)
  end