Use of Breakpoint class should be bdb.Breakpoint.
diff --git a/Tools/idle/Debugger.py b/Tools/idle/Debugger.py
index 0b2e01c..7cb2fdb 100644
--- a/Tools/idle/Debugger.py
+++ b/Tools/idle/Debugger.py
@@ -289,4 +289,4 @@
 	list = self.breaks[filename]
 	if not lineno in list:
 		list.append(lineno)
-	bp = Breakpoint(filename, lineno, temporary, cond)
+	bp = bdb.Breakpoint(filename, lineno, temporary, cond)