How to use the imutils.video.WebcamVideoStream function in imutils

def main():
	global capture
	global Classifier
	global FacenetHelpers
	Classifier = Classifier()
	FacenetHelpers = FacenetHelpers()

	try:
		
		capture = WebcamVideoStream(src=Classifier._configs["Cameras"][0]["URL"]).start()
		print("-- CONNECTED TO WEBCAM")

	except Exception as e:
		print("-- FAILED TO CONNECT TO WEBCAM")
		print(str(e))
		sys.exit()

	try:
		server = ThreadedHTTPServer((Classifier._configs["Cameras"][0]["Stream"], Classifier._configs["Cameras"][0]["StreamPort"]), CamHandler)
		print("-- Server started on "+Classifier._configs["Cameras"][0]["Stream"]+":"+str(Classifier._configs["Cameras"][0]["StreamPort"]))
		server.serve_forever()
	except KeyboardInterrupt:
		server.socket.close()

def main():
	global capture
	global Classifier
	global FacenetHelpers
	Classifier = Classifier()
	FacenetHelpers = FacenetHelpers()

	try:
		
		capture = WebcamVideoStream(src=Classifier._configs["Cameras"][0]["URL"]).start()
		print("-- CONNECTED TO WEBCAM")

	except Exception as e:
		print("-- FAILED TO CONNECT TO WEBCAM")
		print(str(e))
		sys.exit()

	try:
		server = ThreadedHTTPServer((Classifier._configs["Cameras"][0]["Stream"], Classifier._configs["Cameras"][0]["StreamPort"]), CamHandler)
		print("server started")
		server.serve_forever()
	except KeyboardInterrupt:
		server.socket.close()

def run_video(self):
        if self.verbose:
            print('No image path specified, reading from camera video feed')

        camera = WebcamVideoStream(src=self.source).start()

        # Set stream size -- TODO: figure out why this isn't working
        # camera.stream.set(cv2.CAP_PROP_FRAME_WIDTH, 640)
        # camera.stream.set(cv2.CAP_PROP_FRAME_HEIGHT, 480)

        timeout = 0

        if self.tuning:
            cv2.namedWindow('Settings')
            cv2.resizeWindow('Settings', 700, 350)

            cv2.createTrackbar('Lower H', 'Settings', self.settings['lower'][0], 255,
                               lambda val: self.update_thresh(True, 0, val))
            cv2.createTrackbar('Lower S', 'Settings', self.settings['lower'][1], 255,
                               lambda val: self.update_thresh(True, 1, val))
            cv2.createTrackbar('Lower V', 'Settings', self.settings['lower'][2], 255,

def __init__(self, path):
		# Export path
		self.path = path
		self.img_count = 0
		if not os.path.exists(self.path):
			os.makedirs(self.path)
		self.recording_csv = open(self.path + 'annotations.csv', 'a')

		# Initialize ROS Subscriber
		rospy.Subscriber('cmd', Point, self.callback, queue_size=1)

		# Open Camera stream
		self.videoStream = WebcamVideoStream().start()
		time.sleep(1.0)
		#rospy.spin()

def __init__(self, id): 
        # self.cap = cv2.VideoCapture(id)
        self.cap = WebcamVideoStream(src = id).start()
        self.cfgfile = "cfg/yolov3.cfg"
        # self.cfgfile = 'cfg/yolov3-tiny.cfg'
        self.weightsfile = "yolov3.weights"
        # self.weightsfile = 'yolov3-tiny.weights'
        self.confidence = float(0.6)
        self.nms_thesh = float(0.8)
        self.num_classes = 80
        self.classes = load_classes('data/coco.names')
        self.colors = pkl.load(open("pallete", "rb"))
        self.model = Darknet(self.cfgfile)
        self.CUDA = torch.cuda.is_available()
        self.model.load_weights(self.weightsfile)
        self.model.net_info["height"] = 160
        self.inp_dim = int(self.model.net_info["height"])
        self.width = 1280 #640#1280
        self.height = 720 #360#720

def run_video(self):
        if self.verbose:
            print("No image path specified, reading from camera video feed")

        camera = WebcamVideoStream(src=self.source).start()

        timeout = 0

        if self.tuning:
            cv2.namedWindow("Settings")
            cv2.resizeWindow("Settings", 700, 350)

            cv2.createTrackbar("Lower H", "Settings", self.lower[0], 255,
                               lambda val: self.update_setting(True, 0, val))
            cv2.createTrackbar("Lower S", "Settings", self.lower[1], 255,
                               lambda val: self.update_setting(True, 1, val))
            cv2.createTrackbar("Lower V", "Settings", self.lower[2], 255,
                               lambda val: self.update_setting(True, 2, val))

            cv2.createTrackbar("Upper H", "Settings", self.upper[0], 255,
                               lambda val: self.update_setting(False, 0, val))

fps.update()

# stop the timer and display FPS information
fps.stop()
print("[INFO] elasped time: {:.2f}".format(fps.elapsed()))
print("[INFO] approx. FPS: {:.2f}".format(fps.fps()))

# do a bit of cleanup
stream.release()
cv2.destroyAllWindows()


# created a *threaded* video stream, allow the camera sensor to warmup,
# and start the FPS counter
print("[INFO] sampling THREADED frames from webcam...")
vs = WebcamVideoStream(src=0).start()
fps = FPS().start()

# loop over some frames...this time using the threaded stream
while fps._numFrames < args["num_frames"]:
	# grab the frame from the threaded video stream and resize it
	# to have a maximum width of 400 pixels
	frame = vs.read()
	frame = imutils.resize(frame, width=400)

	# check to see if the frame should be displayed to our screen
	if args["display"] > 0:
		cv2.imshow("Frame", frame)
		key = cv2.waitKey(1) & 0xFF

	# update the FPS counter
	fps.update()

def __init__(self, path):
		# Export path
		self.path = path
		if not os.path.exists(self.path):
			os.makedirs(self.path)
		self.recording_csv = open(self.path + 'annotations.csv', 'a')

		# Initialize ROS Subscriber
		rospy.init_node('data_saver', anonymous=True)
		rospy.Subscriber('cmd', Point, self.callback)

		# Open Camera stream
		self.videoStream = WebcamVideoStream().start()
		time.sleep(1.0)
		rospy.spin()

from imutils.video import WebcamVideoStream
import numpy as np
import argparse
import imutils
import time
import cv2

print("[INFO] starting video thread...")
wvs = WebcamVideoStream().start()
time.sleep(1.0)


# loop over frames from the video file stream
while True:
	frame = wvs.read()
	#frame = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
	#frame = np.dstack([frame, frame, frame])
	cv2.imshow("Frame", frame)
	cv2.waitKey(1)
	#fps.update()

# do a bit of cleanup
cv2.destroyAllWindows()
wvs.stop()

for i in range(detections.size(1)):
            j = 0
            while detections[0, i, j, 0] >= 0.6:
                pt = (detections[0, i, j, 1:] * scale).cpu().numpy()
                cv2.rectangle(frame,
                              (int(pt[0]), int(pt[1])),
                              (int(pt[2]), int(pt[3])),
                              COLORS[i % 3], 2)
                cv2.putText(frame, labelmap[i - 1], (int(pt[0]), int(pt[1])),
                            FONT, 2, (255, 255, 255), 2, cv2.LINE_AA)
                j += 1
        return frame

    # start video stream thread, allow buffer to fill
    print("[INFO] starting threaded video stream...")
    stream = WebcamVideoStream(src=0).start()  # default camera
    time.sleep(1.0)
    # start fps timer
    # loop over frames from the video file stream
    while True:
        # grab next frame
        frame = stream.read()
        key = cv2.waitKey(1) & 0xFF

        # update FPS counter
        fps.update()
        frame = predict(frame)

        # keybindings for display
        if key == ord('p'):  # pause
            while True:
                key2 = cv2.waitKey(1) or 0xff