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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 _compute_experiment_from_runs(self):
 """Computes a minimal Experiment protocol buffer by scanning the runs."""

    hparam_infos = self._compute_hparam_infos()
    if not hparam_infos:
      return None
    metric_infos = self._compute_metric_infos()
    return api_pb2.Experiment(hparam_infos=hparam_infos,
                              metric_infos=metric_infos)