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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 _create_extractors(cls, metrics):
 """Build metrics extractors according to the `metrics` config :param metrics: Benchmark `metrics` configuration section """

        metrics_dict = {}
        # group entries by `category` attribute (default is "standard")
        for metric, config in six.iteritems(metrics):
            category = config.get('category', StdBenchmark.DEFAULT_CATEGORY)
            metrics_dict.setdefault(category, {})[metric] = config
        # create one StdExtractor instance per category,
        # passing associated metrics
        return dict(
            (category, StdExtractor(metrics))
            for category, metrics in six.iteritems(metrics_dict)
        )