incremental testing in all()

[DeaD_EyE]

Here the proof without have to read C.

deadeye@nexus ~ $ ipython                                                                                                       
Python 3.7.4 (default, Jul 10 2019, 23:32:01) 
Type 'copyright', 'credits' or 'license' for more information
IPython 7.7.0 -- An enhanced Interactive Python. Type '?' for help.

In [1]: class Iterator: 
   ...:     def __init__(self): 
   ...:         self.last = None 
   ...:          
   ...:     def __iter__(self): 
   ...:         for i in range(10): 
   ...:             print(i) 
   ...:             if i < 5: 
   ...:                 yield True 
   ...:             else: 
   ...:                 yield False 
   ...:                                                                                                                         

In [2]: all(Iterator())                                                                                                         
0
1
2
3
4
5
Out[2]: False

The loop is stopped, when False is yielded.