example of __del__ drawback: order of clearing globals not promised

__del__.py

In [2]: # %load risk_of__del__globals_cleanup.py 
   ...: import gc 
   ...:  
   ...: class GlobalCounter: 
   ...:     value = 0 
   ...:  
   ...:  
   ...: class SomeKlass: 
   ...:     def __del__(self): 
   ...:         print('in SomeKlass __del__') 
   ...:         GlobalCounter.value+=1 
   ...:  
   ...: klass = SomeKlass() 
   ...:  
   ...: #GlobalCounter.value+=1 
   ...:  
   ...: #GlobalCounter.value 
   ...:  
   ...: #klass 
   ...:  
   ...:  
   ...:                                                                                                                    

In [3]: klass                                                                                                              
Out[3]: <__main__.SomeKlass at 0x7fa6fa4141f0>

In [4]: GlobalCounter.value+=1                                                                                             

In [5]: GlobalCounter.value                                                                                                
Out[5]: 1

In [6]: klass                                                                                                              
Out[6]: <__main__.SomeKlass at 0x7fa6fa4141f0>

In [7]:                                                                                                                    
Do you really want to exit ([y]/n)? y
in SomeKlass __del__
Exception ignored in: <function SomeKlass.__del__ at 0x7fa6fbee1b80>
Traceback (most recent call last):
  File "<ipython-input-2-d7f50334a983>", line 11, in __del__
NameError: name 'GlobalCounter' is not defined