human
Solve the following python programming problem given the following code:
def prefer_isolation(self, index) : 
    '
        For nodes that are not yet isoleted. (SimpleNodes, or normal Nodes
        nested in there.) yield the isolations with this index.  Otherwise,
        nodes are yielded unmodified.
        ' 
    def new_iterator() : 
        for n in self : 
            if (not n._node_is_isolated) : 
                try : 
                    (yield n [index]) 
except KeyError : 
                    pass 
else : 
                (yield n) 
return NodeIterator (index) 

    
    

    Fix the buggy line: return NodeIterator (index)
assistant
#Here is Python code to fix the buggy line: return NodeIterator (index)
.

return NodeIterator (def new_iterator()