Error checking was too aggressive (reported by Chris Tismer)
diff --git a/Lib/test/test_collections.py b/Lib/test/test_collections.py
index 52bae9a..0b0b029 100644
--- a/Lib/test/test_collections.py
+++ b/Lib/test/test_collections.py
@@ -29,6 +29,7 @@
         self.assertRaises(ValueError, namedtuple, 'abc', 'efg efg ghi')    # duplicate field
 
         namedtuple('Point0', 'x1 y2')   # Verify that numbers are allowed in names
+        namedtuple('_', '_ __ ___')     # Verify that underscores are allowed
 
     def test_instance(self):
         Point = namedtuple('Point', 'x y')