code: def OPTIONS_preflight( self, path_info ):
          
          self.send_response(200)
          self.send_header('Access-Control-Allow-Origin', '*')    # CORS
          self.send_header('Access-Control-Allow-Methods', 'GET, PUT, POST, DELETE')
          self.send_header('Access-Control-Allow-Headers', 'content-type, authorization, range')
          self.send_header('Access-Control-Expose-Headers', 'content-length, content-range')
          self.send_header('Access-Control-Max-Age', 21600)
          self.end_headers()
          return
docs: Give back CORS preflight check headers