How to call a function if a Face is detected OpenCV

I want to call a function if a face is detected in OpenCV.

Can someone help I used OpenCV to recognize the Face Can i add an if-statement somewhere do display the function called "Nachricht"? I would appreciate any help.

Thank you in advance :)

the code:

`

def Nachricht():
    hr = ToastNotifier()
    hr.show_toast("Gesicht erkannt", "Gesicht wurde erkannt")



recognizer = cv2.face.LBPHFaceRecognizer_create()
recognizer.read("trainer.yml")

labels = {"person_name": 1}
with open("labels.pickle", 'rb') as f:
    og_labels = pickle.load(f)
    labels = {v:k for k,v in og_labels.items()}

cap = cv2.VideoCapture(0)

while(True):
   
    ret, frame = cap.read()
    gray  = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
    faces = face_cascade.detectMultiScale(gray, scaleFactor=1.5, minNeighbors=5)
    for (x, y, w, h) in faces:
        roi_gray = gray[y:y+h, x:x+w]
        roi_color = frame[y:y+h, x:x+w]

        
        id_, conf = recognizer.predict(roi_gray)
        if conf>=4 and conf <= 85:
            
            font = cv2.FONT_HERSHEY_SIMPLEX
            name = labels[id_]
            color = (255, 255, 255)
            stroke = 2
            cv2.putText(frame, name, (x,y), font, 1, color, stroke, cv2.LINE_AA)



        color = (255, 0, 0)
        stroke = 2
        end_cord_x = x + w
        end_cord_y = y + h
        cv2.rectangle(frame, (x, y), (end_cord_x, end_cord_y), color, stroke)
        


cv2.imshow('frame',frame)
    if cv2.waitKey(20) & 0xFF == ord('b'):
        break



cap.release()
cv2.destroyAllWindows()`