Index: pyyaml/trunk/lib/yaml/detector.py
===================================================================
--- pyyaml/trunk/lib/yaml/detector.py	(revision 133)
+++ pyyaml/trunk/lib/yaml/detector.py	(revision 136)
@@ -6,5 +6,12 @@
 class BaseDetector:
 
+    DEFAULT_SCALAR_TAG = u'tag:yaml.org,2002:str'
+    DEFAULT_SEQUENCE_TAG = u'tag:yaml.org,2002:seq'
+    DEFAULT_MAPPING_TAG = u'tag:yaml.org,2002:map'
+
     yaml_detectors = {}
+
+    def __init__(self):
+        pass
 
     def add_detector(cls, tag, regexp, first):