def extract_metrics(self, metrics_files):
        """Return summary information for a lane of 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
Return summary information for a lane of metrics files.