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: piv_cac_verification_controller.rb
    path of file: ./repos/identity-idp/app/controllers/two_factor_authentication
    
    the code of the file until where you have to start completion: module TwoFactorAuthentication
  class PivCacVerificationController < ApplicationController
    include TwoFactorAuthenticatable
    include PivCacConcern

    before_
    
    def process_token
      result = piv_cac_verification_form.submit
      analytics.track_mfa_submit_event(
        result.to_h.merge(analytics_properties),
      )
      irs_attempts_api_tracker.mfa_login_piv_cac(
        success: result.success?,
        subject_dn: piv_cac_verification_form.x509_dn,
      )
      session[:sign_in_flow] = :sign_in
      if result.success?
        handle_valid_piv_cac
      else
        handle_invalid_piv_cac
      end