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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def label_total_duration(self, label_list_ids=None):
 """ Return a dictionary containing the number of seconds, every label-value is occurring in this utterance. Args: label_list_ids (list):
 If not None, only labels from label-lists with an id contained in this list are considered. Returns: dict: A dictionary containing the number of seconds with the label-value as key. """

        duration = collections.defaultdict(float)

        for label_list in self.label_lists.values():
            if label_list_ids is None or label_list.idx in label_list_ids:
                for label_value, label_duration in label_list.label_total_duration().items():
                    duration[label_value] += label_duration

        return duration