+ namespace = self._search_regex(r'(?i)^{([^}]+)?}MPD$', mpd_doc.tag, 'namespace', default=None)
+
+ def _add_ns(path):
+ return self._xpath_ns(path, namespace)
+
+ def is_drm_protected(element):
+ return element.find(_add_ns('ContentProtection')) is not None
+