How to use the djitellopy.Tello function in djitellopy

def __init__(self):
        # Init pygame
        pygame.init()

        # Creat pygame window
        pygame.display.set_caption("Tello video stream")
        self.screen = pygame.display.set_mode([960, 720])

        # Init Tello object that interacts with the Tello drone
        self.tello = Tello()

        # Drone velocities between -100~100
        self.for_back_velocity = 0
        self.left_right_velocity = 0
        self.up_down_velocity = 0
        self.yaw_velocity = 0
        self.speed = 10

        self.send_rc_control = False

        # create update timer
        pygame.time.set_timer(pygame.USEREVENT + 1, 1000 // FPS)

def __init__(self):
        # Init Tello object that interacts with the Tello drone
        self.tello = Tello()

        # Drone velocities between -100~100
        self.for_back_velocity = 0
        self.left_right_velocity = 0
        self.up_down_velocity = 0
        self.yaw_velocity = 0
        self.speed = 10

        self.send_rc_control = False

# simple example demonstrating how to control a Tello using your keyboard.
# For a more fully featured example see manual-control-pygame.py
# 
# Use W, A, S, D for moving, E, Q for rotating and R, F for going up and down.
# When starting the script the Tello will takeoff, pressing ESC makes it land
#  and the script exit.

from djitellopy import Tello
import cv2, math, time

tello = Tello()
tello.connect()

tello.streamon()
frame_read = tello.get_frame_read()

tello.takeoff()

while True:
    # In reality you want to display frames in a seperate thread. Otherwise
    #  they will freeze while the drone moves.
    img = frame_read.frame
    cv2.imshow("drone", img)

    key = cv2.waitKey(1) & 0xff
    if key == 27: # ESC
        break