Expanded class wrapper demo to explain it's not a recommended design pattern. When initially released there was no explanation accompanying the code.

DemoPrograms/Demo_Class_Wrapper.py

@@ -5,9 +5,37 @@ import PySimpleGUI as sg
     
     Using a class to encapsulate PySimpleGUI Window creation & event loop
     
-    Copyright 2022 PySimpleGUI
+    This is NOT a recommended design pattern.  It mimics the object oriented design that many OO-based
+    GUI frameworks use, but there is no advantage to structuring you code in his manner.  It adds
+    confusion, not clarity.  
+    
+    The class version is 18 lines of code.  The plain version is 11 lines of code.  
+    
+    Two things about the class wrapper jump out as adding confusion:
+    1. Unneccessary fragmentation of the event loop - the button click code is pulled out of the loop entirely
+    2. "self" clutters the code without adding value
+    
+
+    Copyright 2022, 2023 PySimpleGUI
 """
 
+'''
+    MM'""""'YMM dP                            
+    M' .mmm. `M 88                            
+    M  MMMMMooM 88 .d8888b. .d8888b. .d8888b. 
+    M  MMMMMMMM 88 88'  `88 Y8ooooo. Y8ooooo. 
+    M. `MMM' .M 88 88.  .88       88       88 
+    MM.     .dM dP `88888P8 `88888P' `88888P' 
+    MMMMMMMMMMM                               
+                                              
+    M""MMMMM""M                            oo                   
+    M  MMMMM  M                                                 
+    M  MMMMP  M .d8888b. 88d888b. .d8888b. dP .d8888b. 88d888b. 
+    M  MMMM' .M 88ooood8 88'  `88 Y8ooooo. 88 88'  `88 88'  `88 
+    M  MMP' .MM 88.  ... 88             88 88 88.  .88 88    88 
+    M     .dMMM `88888P' dP       `88888P' dP `88888P' dP    dP 
+    MMMMMMMMMMM
+'''
 class SampleGUI():
 
     def __init__(self):
@@ -35,3 +63,39 @@ class SampleGUI():
 my_gui = SampleGUI()
 # run the event loop
 my_gui.run()
+
+
+'''
+    M"""""""`YM                                       dP 
+    M  mmmm.  M                                       88 
+    M  MMMMM  M .d8888b. 88d888b. 88d8b.d8b. .d8888b. 88 
+    M  MMMMM  M 88'  `88 88'  `88 88'`88'`88 88'  `88 88 
+    M  MMMMM  M 88.  .88 88       88  88  88 88.  .88 88 
+    M  MMMMM  M `88888P' dP       dP  dP  dP `88888P8 dP 
+    MMMMMMMMMMM                                          
+                                                         
+    M""MMMMM""M                            oo                   
+    M  MMMMM  M                                                 
+    M  MMMMP  M .d8888b. 88d888b. .d8888b. dP .d8888b. 88d888b. 
+    M  MMMM' .M 88ooood8 88'  `88 Y8ooooo. 88 88'  `88 88'  `88 
+    M  MMP' .MM 88.  ... 88             88 88 88.  .88 88    88 
+    M     .dMMM `88888P' dP       `88888P' dP `88888P' dP    dP 
+    MMMMMMMMMMM
+'''
+
+layout = [ [sg.Text('My layout')],
+         [sg.Input(key='-IN-')],
+         [sg.Button('Go'), sg.Button('Exit')] ]
+
+window = sg.Window('My new window', layout)
+
+while True:             # Event Loop
+    event, values = window.read()
+    if event in (sg.WIN_CLOSED, 'Exit'):
+        break
+
+    if event == 'Go':
+        sg.popup('Go button clicked', 'Input value:', values['-IN-'])
+
+window.close()
+