register_namespace was introduced in python 2.7 xml.etree

fastkml/test_main.py

@@ -122,9 +122,14 @@ class BuildKmlTestCase(unittest.TestCase):
         if config.LXML:
             self.assertEqual( str(k.to_string())[:43],
             '<kml xmlns="http://www.opengis.net/kml/2.2"/>'[:43])
+        else:
+            if hasattr(etree, 'register_namespace'):
+                self.assertEqual(str(k.to_string())[:51],
+                '<kml:kml xmlns:kml="http://www.opengis.net/kml/2.2" />'[:51])
             else:
                 self.assertEqual(str(k.to_string())[:51],
                 '<ns0:kml xmlns:ns0="http://www.opengis.net/kml/2.2" />'[:51])
+
         k2 = kml.KML()
         k2.from_string(k.to_string())
         self.assertEqual(k.to_string(), k2.to_string())