diff --git a/ryu/app/event_dumper.py b/ryu/app/event_dumper.py
index 647f8da9..475e12ef 100644
--- a/ryu/app/event_dumper.py
+++ b/ryu/app/event_dumper.py
@@ -32,6 +32,7 @@ gflags.DEFINE_multistring('dump_dispatcher', [],
 
 class EventDumper(object):
     def __init__(self, *_args, **_kwargs):
+        super(EventDumper, self).__init__()
         # EventDispatcher can be created and cloned before us.
         # So register it explicitly
         for ev_q in dispatcher.EventQueue.all_instances():
diff --git a/ryu/app/simple_switch.py b/ryu/app/simple_switch.py
index a14bdb4f..95d09424 100644
--- a/ryu/app/simple_switch.py
+++ b/ryu/app/simple_switch.py
@@ -36,6 +36,7 @@ LOG = logging.getLogger('ryu.app.simple_switch')
 
 class SimpleSwitch(object):
     def __init__(self, *_args, **_kwargs):
+        super(SimpleSwitch, self).__init__()
         self.mac2port = mac_to_port.MacToPortTable()
 
     @set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER)
diff --git a/ryu/controller/dispatcher.py b/ryu/controller/dispatcher.py
index 47248285..112c97b1 100644
--- a/ryu/controller/dispatcher.py
+++ b/ryu/controller/dispatcher.py
@@ -43,6 +43,7 @@ class EventQueue(TrackInstances):
             ev_q.queue(ev)
 
     def __init__(self, name, dispatcher, aux=None):
+        super(EventQueue, self).__init__()
         self.name = name
         self._dispatcher = dispatcher.clone()
         self.is_dispatching = False
@@ -113,6 +114,7 @@ class EventQueue(TrackInstances):
 
 class EventDispatcher(TrackInstances):
     def __init__(self, name):
+        super(EventDispatcher, self).__init__()
         self.parent = None
         self.children = set()
         self.name = name
diff --git a/ryu/controller/mac_to_network.py b/ryu/controller/mac_to_network.py
index e5f5a921..dd2c4efe 100644
--- a/ryu/controller/mac_to_network.py
+++ b/ryu/controller/mac_to_network.py
@@ -24,6 +24,7 @@ LOG = logging.getLogger('ryu.controller.mac_to_network')
 
 class MacToNetwork(object):
     def __init__(self, nw):
+        super(MacToNetwork, self).__init__()
         self.mac_to_net = {}
         self.dpid = {}
         self.nw = nw
diff --git a/ryu/controller/mac_to_port.py b/ryu/controller/mac_to_port.py
index 4d05a36d..98472a2f 100644
--- a/ryu/controller/mac_to_port.py
+++ b/ryu/controller/mac_to_port.py
@@ -24,6 +24,7 @@ class MacToPortTable(object):
     """MAC addr <-> (dpid, port name)"""
 
     def __init__(self):
+        super(MacToPortTable, self).__init__()
         self.mac_to_port = {}
 
     def dpid_add(self, dpid):