How to use the airsim.write_file function in airsim

def take_snapshot(self):
        # first hold our current position so drone doesn't try and keep flying while we take the picture.
        pos = self.client.getMultirotorState().kinematics_estimated.position
        self.client.moveToPositionAsync(pos.x_val, pos.y_val, self.z, 0.5, 10, airsim.DrivetrainType.MaxDegreeOfFreedom, 
            airsim.YawMode(False, self.camera_heading)).join()
        responses = self.client.simGetImages([airsim.ImageRequest(1, airsim.ImageType.Scene)]) #scene vision image in png format
        response = responses[0]
        filename = "photo_" + str(self.snapshot_index)
        self.snapshot_index += 1
        airsim.write_file(os.path.normpath(filename + '.png'), response.image_data_uint8)        
        print("Saved snapshot: {}".format(filename))
        self.start_time = time.time()  # cause smooth ramp up to happen again after photo is taken.

def take_snapshot(self):
        if not os.path.exists(self.image_dir):
            os.makedirs(self.image_dir)

        # first hold our current position so drone doesn't try and keep flying while we take the picture.
        pos = self.client.getMultirotorState().kinematics_estimated.position
        self.client.moveToPositionAsync(pos.x_val, pos.y_val, self.z, 0.25, 3, airsim.DrivetrainType.MaxDegreeOfFreedom,
                                        airsim.YawMode(False, self.camera_heading))
        responses = self.client.simGetImages([airsim.ImageRequest(
            0, airsim.ImageType.Scene)])  # scene vision image in png format
        response = responses[0]
        filename = self.photo_prefix + \
            str(self.snapshot_index) + "_" + str(int(time.time()))
        self.snapshot_index += 1
        airsim.write_file(os.path.normpath(
            self.image_dir + filename + '.png'), response.image_data_uint8)
        print("Saved snapshot: {}".format(filename))
        # cause smooth ramp up to happen again after photo is taken.
        self.start_time = time.time()

airsim.ImageRequest("1", airsim.ImageType.Scene, False, False)], "Car1")  #scene vision image in uncompressed RGBA array
    print('Car1: Retrieved images: %d' % (len(responses1)))
    responses2 = client.simGetImages([
        airsim.ImageRequest("0", airsim.ImageType.Segmentation),  #depth visualization image
        airsim.ImageRequest("1", airsim.ImageType.Scene, False, False)], "Car2")  #scene vision image in uncompressed RGBA array
    print('Car2: Retrieved images: %d' % (len(responses2)))

    for response in responses1 + responses2:
        filename = 'c:/temp/car_multi_py' + str(idx)

        if response.pixels_as_float:
            print("Type %d, size %d" % (response.image_type, len(response.image_data_float)))
            airsim.write_pfm(os.path.normpath(filename + '.pfm'), airsim.get_pfm_array(response))
        elif response.compress: #png format
            print("Type %d, size %d" % (response.image_type, len(response.image_data_uint8)))
            airsim.write_file(os.path.normpath(filename + '.png'), response.image_data_uint8)
        else: #uncompressed array
            print("Type %d, size %d" % (response.image_type, len(response.image_data_uint8)))
            img1d = np.fromstring(response.image_data_uint8, dtype=np.uint8) #get numpy array
            img_rgba = img1d.reshape(response.height, response.width, 4) #reshape array to 4 channel image array H X W X 4
            img_rgba = np.flipud(img_rgba) #original image is flipped vertically
            img_rgba[:,:,1:2] = 100 #just for fun add little bit of green in all pixels
            airsim.write_png(os.path.normpath(filename + '.greener.png'), img_rgba) #write to png 


#restore to original state
client.reset()

client.enableApiControl(False)

responses = client.simGetImages([
        airsim.ImageRequest("0", airsim.ImageType.DepthVis),
        airsim.ImageRequest("1", airsim.ImageType.DepthPerspective, True),
        airsim.ImageRequest("2", airsim.ImageType.Segmentation),
        airsim.ImageRequest("3", airsim.ImageType.Scene),
        airsim.ImageRequest("4", airsim.ImageType.DisparityNormalized),
        airsim.ImageRequest("4", airsim.ImageType.SurfaceNormals)])

    for i, response in enumerate(responses):
        if response.pixels_as_float:
            print("Type %d, size %d, pos %s" % (response.image_type, len(response.image_data_float), pprint.pformat(response.camera_position)))
            airsim.write_pfm(os.path.normpath('/temp/cv_mode_' + str(x) + "_" + str(i) + '.pfm'), airsim.get_pfm_array(response))
        else:
            print("Type %d, size %d, pos %s" % (response.image_type, len(response.image_data_uint8), pprint.pformat(response.camera_position)))
            airsim.write_file(os.path.normpath('/temp/cv_mode_' + str(x) + "_" + str(i) + '.png'), response.image_data_uint8)

    pose = client.simGetVehiclePose()
    pp.pprint(pose)

    time.sleep(3)

# currently reset() doesn't work in CV mode. Below is the workaround
client.simSetPose(airsim.Pose(airsim.Vector3r(0, 0, 0), airsim.to_quaternion(0, 0, 0)), True)

try:
    os.makedirs(tmp_dir)
except OSError:
    if not os.path.isdir(tmp_dir):
        raise

for idx, response in enumerate(responses1 + responses2):

    filename = os.path.join(tmp_dir, str(idx))

    if response.pixels_as_float:
        print("Type %d, size %d" % (response.image_type, len(response.image_data_float)))
        airsim.write_pfm(os.path.normpath(filename + '.pfm'), airsim.get_pfm_array(response))
    elif response.compress: #png format
        print("Type %d, size %d" % (response.image_type, len(response.image_data_uint8)))
        airsim.write_file(os.path.normpath(filename + '.png'), response.image_data_uint8)
    else: #uncompressed array
        print("Type %d, size %d" % (response.image_type, len(response.image_data_uint8)))
        img1d = np.fromstring(response.image_data_uint8, dtype=np.uint8) #get numpy array
        img_rgba = img1d.reshape(response.height, response.width, 4) #reshape array to 4 channel image array H X W X 4
        img_rgba = np.flipud(img_rgba) #original image is flipped vertically
        img_rgba[:,:,1:2] = 100 #just for fun add little bit of green in all pixels
        airsim.write_png(os.path.normpath(filename + '.greener.png'), img_rgba) #write to png

airsim.wait_key('Press any key to reset to original state')

client.armDisarm(False, "Drone1")
client.armDisarm(False, "Drone2")
client.reset()

# that's enough fun for now. let's quit cleanly
client.enableApiControl(False, "Drone1")

airsim.wait_key('Press any key to get images')
for x in range(3): # do few times
    responses = client.simGetImages([
        airsim.ImageRequest("0", airsim.ImageType.DepthVis),
        airsim.ImageRequest("0", airsim.ImageType.Segmentation),
        airsim.ImageRequest("0", airsim.ImageType.Scene),
        airsim.ImageRequest("0", airsim.ImageType.SurfaceNormals)])

    for i, response in enumerate(responses):
        if response.pixels_as_float:
            print("Type %d, size %d, pos %s" % (response.image_type, len(response.image_data_float), pprint.pformat(response.camera_position)))
            airsim.write_pfm(os.path.normpath('/temp/cv_mode_' + str(x) + "_" + str(i) + '.pfm'), airsim.get_pfm_array(response))
        else:
            print("Type %d, size %d, pos %s" % (response.image_type, len(response.image_data_uint8), pprint.pformat(response.camera_position)))
            airsim.write_file(os.path.normpath('/temp/cv_mode_' + str(x) + "_" + str(i) + '.png'), response.image_data_uint8)

    pose = client.simGetVehiclePose()
    pose.position.x_val = pose.position.x_val + 1
    pose.position.y_val = pose.position.y_val - 0.5
    pose.position.z_val = pose.position.z_val - 0.5
    client.simSetVehiclePose(pose, True)

    time.sleep(3)

client.reset()