code: def extract_metrics(self, metrics_files):
          
          extension_maps = dict(
              align_metrics=(self._parse_align_metrics, "AL"),
              dup_metrics=(self._parse_dup_metrics, "DUP"),
              hs_metrics=(self._parse_hybrid_metrics, "HS"),
              insert_metrics=(self._parse_insert_metrics, "INS"),
              rnaseq_metrics=(self._parse_rnaseq_metrics, "RNA"))
          all_metrics = dict()
          for fname in metrics_files:
              ext = os.path.splitext(fname)[-1][1:]
              try:
                  parse_fn, prefix = extension_maps[ext]
              except KeyError:
                  parse_fn = None
              if parse_fn:
                  with open(fname) as in_handle:
                      for key, val in parse_fn(in_handle).items():
                          if not key.startswith(prefix):
                              key = "%s_%s" % (prefix, key)
                          all_metrics[key] = val
          return all_metrics
docs: Return summary information for a lane of metrics files.