Jupyter-Lab: Kernel is died and restarting while show matplotlib plots

[HebaGamalElDin]

I'm trying to plot some cropped images of my data with matplotlib, but it always showing this message after running the code cell:

the code snippest;

import matplotlib.pyplot as plt
import numpy as np
#import helper

%matplotlib inline

def imshow(img):
    npimg = img.numpy()
    plt.imshow(np.transpose(npimg, (1, 2, 0)))

fig = plt.figure(figsize=(20, 4))
plot_size=20
for idx in np.arange(plot_size):
    ax = fig.add_subplot(2, plot_size/2, idx+1, xticks=[], yticks=[])
    imshow(images[idx])

Environment: Jupyter-lab Python 3.7 Conda environment: Base matplotlib version: 3.3.4 OS: Windows 10 pro