code: def dropbox_submission(dropbox, request):
      
      try:
          data = dropbox_schema.deserialize(request.POST)
      except Exception:
          return HTTPFound(location=request.route_url('dropbox_form'))
  
      # set the message
      dropbox.message = data.get('message')
  
      # recognize submission from watchdog
      if 'testing_secret' in dropbox.settings:
          dropbox.from_watchdog = is_equal(
              unicode(dropbox.settings['test_submission_secret']),
              data.pop('testing_secret', u''))
  
      # a non-js client might have uploaded an attachment via the form's fileupload field:
      if data.get('upload') is not None:
          dropbox.add_attachment(data['upload'])
  
      # now we can call the process method
      dropbox.submit()
      drop_url = request.route_url('dropbox_view', drop_id=dropbox.drop_id)
      print("Created dropbox %s" % drop_url)
      return HTTPFound(location=drop_url)
docs: handles the form submission, redirects to the dropbox's status page.