human
Solve the following python programming problem given the following code:
def get_context_data(self, **kwargs) : 
    ' Utility method when you want to display nested objects
            (such as during a bulk update/delete)
        ' 
    context = super (BaseListAction, self).get_context_data () 
    def _format_callback(obj) : 
        opts = utils.model_options (obj) 
        return ('%s: %s' % (force_text (capfirst (opts.verbose_name)), force_text (obj))) 
collector = utils.NestedObjects (using = None) 
    collector.collect (self.queryset) 
    context.update ({ 
        'view' : self, 
        'objects_name' : self.objects_name, 
        'queryset' : _format_callback.queryset, 
        'deletable_objects' : collector.nested (_format_callback), 
}) 
    return context 

    
    

    Fix the buggy line: 'queryset' : _format_callback.queryset ,
assistant
#Here is Python code to fix the buggy line: 'queryset' : _format_callback.

'queryset' : self.queryset ,