diff --git a/Lib/urllib2.py b/Lib/urllib2.py
index 042f2ba6f2c..992c83b5a1d 100644
--- a/Lib/urllib2.py
+++ b/Lib/urllib2.py
@@ -217,7 +217,8 @@ def get_full_url(self):
     def get_type(self):
         if self.type is None:
             self.type, self.__r_type = splittype(self.__original)
-            assert self.type is not None, self.__original
+            if self.type is None:
+                raise ValueError, "unknown url type: %s" % self.__original
         return self.type
 
     def get_host(self):