Python: if X is detected more than T seconds:

I am looking for Knowledge.

I'm new to python and need to do a project with a camera Gravity: HuskyLens. It allows you to display blocks when it detects faces (around the face, it's tracking in summary) And I would like, when I detect a Block, to know if it is detected for more than 7 seconds.

import time
import json
from huskylib import HuskyLensLibrary

# Initialize
#hl = HuskyLensLibrary("I2C", "", address = 0x32)
hl = HuskyLensLibrary("SERIAL", "/dev/ttyUSB0", 3000000)

# Change to face recognition algorithms
hl.algorithms("ALGORITHM_FACE_RECOGNITION")

timer = time.time()

while True:
    blocks = hl.requestAll()

    for block in blocks:
        if block.type == "BLOCK": # If a block is detected
            print("Face !")
            if BLOCK DETECTED MORE THAN 7 SECONDS: # If a block is detected more than 7 seconds
                print("SCREAMER ! BOO !")
                time.sleep(0.5)
        else:
            print("No Face !")
            time.sleep(0.5)

I do not know if it is sufficiently clear, I am interested in any information allowing me to progress

ps: I have already gone for a walk on the Time library but I have not managed to understand everything and therefore find my happiness.