In the following code facing this error

def train_classifier(self):
        data_dir = "Photo_data"
        path = [os.path.join(data_dir, file) for file in os.listdir(data_dir)]

        faces = []
        ids = []

        for image in path:
            img = Image.open(image).convert('L')  #Gray scale image
            image_np = np.array(img, 'uint8')
            id = int(os.path.split(image)[1].split('.')[1])

            faces.append(image_np)
            ids.append(id)
            cv2.imshow("Training", image_np)
            cv2.waitKey(1) == 13
        ids = np.array(ids)

        # Train the classifier and save
        clf = cv2.face.LBPHFaceRecognizer_create()
        clf.train(faces, ids)
        clf.write("classifier.xml")
        cv2.destroyAllWindows()
        messagebox.showinfo("Result", "Training Photo sample Completed!!")

Error:
cv2.error: OpenCV(4.9.0) /io/opencv_contrib/modules/face/src/lbph_faces.cpp:362: error: (-210:Unsupported format or combination of formats) Empty training data was given. You’ll need more than one sample to learn a model. in function ‘train’

Tried uninstalling opencv-python then installed opencv-contrib-python using pip