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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 _build_metric_list_to_collect(self, additional_metrics):
 """ Build the metric list to collect based on the instance preferences. """

        metrics_to_collect = {}

        # Defaut metrics
        for default_metrics in itervalues(self.DEFAULT_METRICS):
            metrics_to_collect.update(default_metrics)

        # Additional metrics metrics
        for option in additional_metrics:
            additional_metrics = self.AVAILABLE_METRICS.get(option)
            if not additional_metrics:
                if option in self.DEFAULT_METRICS:
                    self.log.warning(
                        u"`%s` option is deprecated. The corresponding metrics are collected by default.", option
                    )
                else:
                    self.log.warning(
                        u"Failed to extend the list of metrics to collect: unrecognized `%s` option", option
                    )
                continue

            self.log.debug(u"Adding `%s` corresponding metrics to the list of metrics to collect.", option)
            metrics_to_collect.update(additional_metrics)

        return metrics_to_collect