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: monthly_gpo_letter_requests_report.rb
    path of file: ./repos/identity-idp/app/jobs/reports
    
    the code of the file until where you have to start completion: require 'identity/hostdata'

module Reports
  class MonthlyGpoLetterRequestsReport < BaseReport
    REPORT_NAME = 'monthly-usps-letter-requests-report'.freeze

    def perform(_date, start_time: first_of_this_month, end_time: end_of_today)
      daily_results = transaction_with_timeout do
        ::LetterRequestsToGpoFtpLog.where(ftp_at: start_time..end_time)
      end
      totals = calculate_t
    
    def perform(_date, start_time: first_of_this_month, end_time: end_of_today)
      daily_results = transaction_with_timeout do
        ::LetterRequestsToGpoFtpLog.where(ftp_at: start_time..end_time)
      end
      totals = calculate_totals(daily_results)
      save_report(
        REPORT_NAME,
        {
          total_letter_requests: totals,
          daily_letter_requests: daily_results,
        }.to_json,
        extension: 'json',
      )
    end