code: def start(self):
      # start a thread to read frames from the file video stream
      self.thread.start()
      return self
  
file_path: imutils/imutils/video/filevideostream.py
imports: from threading import Thread
  import sys
  import cv2
  import time
label_desc: Use image node_id 2 for calling the FileVideoStream obj's underlying member method code with example usage: obj.start() and returns: self