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: pdf.rb
    path of file: ./repos/pivorak-web-app/app/services/visit_request/qr_code
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

class VisitRequest
  module QrCode
    class Pdf < ApplicationService
      def initialize(visit_request)
        @visit_request = visit_request
      end

      def call
        check_in_url = VisitRequest::QrCode::Url.call(vis
    
      def call
        check_in_url = VisitRequest::QrCode::Url.call(visit_request)

        pdf_document = Prawn::Document.new(page_size: 'A4') do
          print_qr_code(check_in_url, extent: 200, stroke: false)
        end

        tempfile = Tempfile.new
        pdf_document.render_file(tempfile)
        tempfile.rewind
        tempfile.read
      end