These classes are Old School

Or Old Style. Roll on, end of Python 2 support.

IPython/core/debugger.py

@@ -256,7 +256,7 b' class Pdb(OldPdb, object):'
         override the same methods from cmd.Cmd to provide prompt toolkit replacement. 
         """
         if not self.use_prompt_toolkit:
-            super(Pdb, self).cmdloop(intro)
+            return OldPdb.cmdloop(self, intro)
 
         if not self.use_rawinput:
             raise ValueError('Sorry ipdb does not support raw_input=False')