How to fix statement seems to have no effect

[hernancrespo89]

Hi, i know there are similar questions but they didn't solve my problem. I have been trying to read brightness of my webcam using OpenCV and QT. I have tried to implement my codes on 3 different files (main,view,model). I created get_brightness in models.py and i call it on views.py but i see statement has no effect warning, and print_brightness never works.

main.py

from PyQt5.QtWidgets import QApplication
from views import UI_Window
from models import Camera

if __name__ == '__main__': #hangi dosyaya sag tiklayip Run dersek o dosya main oluyor. eger dosya main ise kosul saglanmis oluyor.

    camera = Camera(0) #0, webcam numarasi

    app = QApplication([])
    start_window = UI_Window(camera)
    start_window.show()
    app.exit(app.exec_())

views.py

from PyQt5.QtCore import QThread, QTimer
from PyQt5.QtWidgets import QLabel, QWidget, QPushButton, QVBoxLayout, QApplication, QHBoxLayout, QMessageBox,  QMainWindow
from PyQt5.QtGui import QPixmap, QImage
from models import Camera


class UI_Window(QWidget):

    def __init__(self, cam_num):
        super().__init__()
        self.cam_num = cam_num
        self.cam_num.open()

        # Create a timer.
        self.timer = QTimer()
        self.timer.timeout.connect(self.nextFrameSlot)
        self.timer.start(1000. / 24)

        self.print_brightness


    def nextFrameSlot(self):

        frame = self.cam_num.read()

        if frame is not None:
            image = QImage(frame, frame.shape[1], frame.shape[0], QImage.Format_RGB888) #	The image is stored using a 24-bit RGB format (8-8-8).
            self.pixmap = QPixmap.fromImage(image)

    def print_brightness(self):
        print(Camera.get_brightness())

models.py

import cv2

class Camera:

    def __init__(self, cam_num):

        self.cap = cv2.VideoCapture(cam_num)
        self.cam_num = cam_num

    def open(self, width=640, height=480, fps=30):
        # vc.set(5, fps)  #set FPS
        self.cap.set(3, width)   # set width #propID =3 yani 3.property si width. 3.property i 480 yap
        self.cap.set(4, height)  # set height

        return self.cap.isOpened()

    def read(self):
        rval, frame = self.cap.read()
        frame = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
        return frame

    def get_brightness(self):
        return self.cap.get(cv2.CAP_PROP_BRIGHTNESS)