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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 add_metric_values(self, values):
 """ Add one set of faked metric values for a particular resource to the metrics response for a particular metric group, for later retrieval. For defined metric groups, see chapter "Metric groups" in the :term:`HMC API` book. Parameters: values (:class:`~zhmclient.FakedMetricObjectValues`):
 The set of metric values to be added. It specifies the resource URI and the targeted metric group name. """

        assert isinstance(values, FakedMetricObjectValues)
        group_name = values.group_name
        if group_name not in self._metric_values:
            self._metric_values[group_name] = []
        self._metric_values[group_name].append(values)
        if group_name not in self._metric_value_names:
            self._metric_value_names.append(group_name)