old_contents: from django.http import HttpResponse
  from invoice.conf import settings
  
  
  def format_currency(amount):
      return u'%s %.2f %s' % (
          settings.INV_CURRENCY_SYMBOL, amount, settings.INV_CURRENCY
      )
  
  
  def pdf_response(draw_funk, file_name, *args, **kwargs):
      response = HttpResponse(content_type='application/pdf')
      response['Content-Disposition'] = 'attachment; filename="%s"' % file_name
      draw_funk(response, *args, **kwargs)
      return response
  
new_contents: from django.http import HttpResponse
  from invoice.conf import settings
  
  
  def format_currency(amount):
      return u"%s %.2f %s" % (
          settings.INV_CURRENCY_SYMBOL, amount, settings.INV_CURRENCY
      )
  
  
  def pdf_response(draw_funk, file_name, *args, **kwargs):
      response = HttpResponse(content_type="application/pdf")
      response["Content-Disposition"] = "attachment; filename='%s'" % file_name
      draw_funk(response, *args, **kwargs)
      return response
  
subject: Change ' to "