How to save two different matplotlib figures to two lists

Question

data = pd.read_csv("Test data.csv")

test_data = np.array(data)

where the test_data is a time series dataset which dimension is 24×1024. Firstly, I use a for loop to draw all raw data and use map method to save raw figures in figs_list. the map method reference is here: Get the list of figures in matplotlib

def raw_data_draw():
    for i in range(len(test_data)):
        draw_data = test_data[i]
        plt.figure(figsize=(3.5,2.4),dpi=100)
        plt.xlim([0,1024])
        plt.ylim([0,1])
        plt.plot(draw_data)
        plt.title("signal %d"%i)
        
    global figs_list
    figs_list = list(map(plt.figure, plt.get_fignums()))
    return figs_list

secondly, I reshape the (24×1024) to (24×32×32) and draw grey scale images.

def grey_data_draw():
    for i in range(len(test_data)):
        grey_data = test_data.reshape(len(test_data),32,-1)
        plt.figure(figsize=(2.5,2.5),dpi=100)
        plt.imshow(grey_data[i],origin='lower', cmap=plt.cm.gray)
        plt.title("signal %d"%i)
    
    global grey_figs_list
    
    grey_figs_list = list(map(plt.figure, plt.get_fignums()))
    return grey_figs_list

Lastly, I run these two functions as follow and get two lists.

raw_data_draw()
grey_data_draw()

the figs_list should contain 24 time series plot and grey_figs_list should contain 24 grey images. I expect that figs_list and grey_figs_list contain different items, anyhow these tow lists contains same items,which seems figure were overwrited. I have searched much material but can not deal with it. Hope you can help me solve this problem, thanks in advance! :) the result is show as follow, where two lists contains same items.