human
Solve the following python programming problem given the following code:
def _all_classes(self, classes) : 
    '
        Return a list of all classes that are ancestors of *classes*.
        ' 
    all_classes = { 
        
} 
    def recurse(cls) : 
        all_classes [cls] = None 
        for c in cls.__bases__ : 
            if (c not in all_classes) : 
                recurse (c) 
for cls in self : 
        recurse (cls) 
return list (all_classes.keys ()) 

    
    

    Fix the buggy line: for cls in self :
assistant
#Here is Python program to fix the buggy line: for cls in self :
.

for cls in classes :