code: def file_detector(self, detector):
          
          if detector is None:
              raise WebDriverException("You may not set a file detector that is null")
          if not isinstance(detector, FileDetector):
              raise WebDriverException("Detector has to be instance of FileDetector")
          self._file_detector = detector
docs: Set the file detector to be used when sending keyboard input.
          By default, this is set to a file detector that does nothing.
  
          see FileDetector
          see LocalFileDetector
          see UselessFileDetector
  
          :Args:
           - detector: The detector to use. Must not be None.