human
Solve the following python programming problem given the following code:
def register_remove_op(self, multi) : 
    collection = self.builder.collection 
    selector = collection.selector 
    def exec_remove() : 
        op_result = collection.remove (selector, multi = multi) 
        if op_result.get ('ok') : 
            return { 
                'nRemoved' : op_result.get ('n'), 
} 
err = op_result.get ('err') 
        if err : 
            return { 
                'writeErrors' : [err], 
} 
return { 
            
} 
self.builder.executors.append (exec_remove) 

    
    

    Fix the buggy line: selector = collection.selector
assistant
#Here is Python program to fix the buggy line: selector = collection.

selector = self.selector