code: def OPTIONS(self, *args, **kwargs):
          
          if not self.cors:
              raise CallError(405)
  
          req = self.request
  
          origin = req.get_header('origin')
          if not origin:
              raise CallError(400, 'Need Origin header') 
          call_headers = [
              ('Access-Control-Request-Headers', 'Access-Control-Allow-Headers'),
              ('Access-Control-Request-Method', 'Access-Control-Allow-Methods')
          ]
          for req_header, res_header in call_headers:
              v = req.get_header(req_header)
              if v:
                  self.response.set_header(res_header, v)
              else:
                  raise CallError(400, 'Need {} header'.format(req_header))
  
          other_headers = {
              'Access-Control-Allow-Credentials': 'true',
              'Access-Control-Max-Age': 3600
          }
          self.response.add_headers(other_headers)
docs: Handles CORS requests for this controller
  
          if self.cors is False then this will raise a 405, otherwise it sets everything
          necessary to satisfy the request in self.response