diff --git a/olt.py b/olt.py
index 12232f4..96851ee 100644
--- a/olt.py
+++ b/olt.py
@@ -931,7 +931,7 @@
 
     def testPacketFlow(self):
         (s_vlan_id, c_vlan_id) = self.vlan_pairs
-        
+
         incorrectTagPkt = simple_udp_packet(pktlen=100, dl_vlan_enable=True, vlan_vid=100, vlan_pcp=0)
         untaggedPkt = simple_udp_packet(pktlen=100, dl_vlan_enable=True, vlan_vid=0, vlan_pcp=0)
 
@@ -962,98 +962,98 @@
         verify_no_packet(self, upstreamDoubleTaggedPkt, olt_port)
 
 
-def installDoubleTaggingRule(self, s_vlan_id, c_vlan_id):
-    # upstream flow rule
-    match = ofp.match()
-    match.oxm_list.append(ofp.oxm.in_port(onu_port))
-    match.oxm_list.append(ofp.oxm.vlan_vid(value=ofp.OFPVID_PRESENT))
-    match.oxm_list.append(ofp.oxm.vlan_pcp(value=0))
-    self.cookie += 1
+    def installDoubleTaggingRule(self, s_vlan_id, c_vlan_id):
+        # upstream flow rule
+        match = ofp.match()
+        match.oxm_list.append(ofp.oxm.in_port(onu_port))
+        match.oxm_list.append(ofp.oxm.vlan_vid(value=ofp.OFPVID_PRESENT))
+        match.oxm_list.append(ofp.oxm.vlan_pcp(value=0))
+        self.cookie += 1
 
-    # push inner vlan (c-vlan) for upstream
-    request = ofp.message.flow_add(
-        table_id=test_param_get("table", 0),
-        cookie=self.cookie,
-        match=match,
-        instructions=[
-            ofp.instruction.apply_actions(
-                actions=[
-                    ofp.action.set_field(ofp.oxm.vlan_vid(ofp.OFPVID_PRESENT | c_vlan_id))]),
-            ofp.instruction.goto_table(1)],
-        buffer_id=ofp.OFP_NO_BUFFER,
-        priority=1000)
+        # push inner vlan (c-vlan) for upstream
+        request = ofp.message.flow_add(
+            table_id=test_param_get("table", 0),
+            cookie=self.cookie,
+            match=match,
+            instructions=[
+                ofp.instruction.apply_actions(
+                    actions=[
+                        ofp.action.set_field(ofp.oxm.vlan_vid(ofp.OFPVID_PRESENT | c_vlan_id))]),
+                ofp.instruction.goto_table(1)],
+            buffer_id=ofp.OFP_NO_BUFFER,
+            priority=1000)
 
-    self.controller.message_send(request)
-    do_barrier(self.controller)
-    verify_no_errors(self.controller)
+        self.controller.message_send(request)
+        do_barrier(self.controller)
+        verify_no_errors(self.controller)
 
-    # push outer vlan (s-vlan) for upstream
-    match = ofp.match()
-    match.oxm_list.append(ofp.oxm.in_port(onu_port))
-    match.oxm_list.append(ofp.oxm.vlan_vid(ofp.OFPVID_PRESENT | c_vlan_id))
-    match.oxm_list.append(ofp.oxm.vlan_pcp(0))
-    self.cookie += 1
+        # push outer vlan (s-vlan) for upstream
+        match = ofp.match()
+        match.oxm_list.append(ofp.oxm.in_port(onu_port))
+        match.oxm_list.append(ofp.oxm.vlan_vid(ofp.OFPVID_PRESENT | c_vlan_id))
+        match.oxm_list.append(ofp.oxm.vlan_pcp(0))
+        self.cookie += 1
 
-    request = ofp.message.flow_add(
-        table_id=test_param_get("table", 1),
-        cookie=self.cookie,
-        match=match,
-        instructions=[
-            ofp.instruction.apply_actions(
-                actions=[
-                    ofp.action.push_vlan(ethertype=0x8100),
-                    ofp.action.set_field(ofp.oxm.vlan_vid(ofp.OFPVID_PRESENT | s_vlan_id)),
-                    ofp.action.set_field(ofp.oxm.vlan_pcp(0)),
-                    ofp.action.output(port=olt_port)]),
-        ],
-        buffer_id=ofp.OFP_NO_BUFFER,
-        priority=1000)
+        request = ofp.message.flow_add(
+            table_id=test_param_get("table", 1),
+            cookie=self.cookie,
+            match=match,
+            instructions=[
+                ofp.instruction.apply_actions(
+                    actions=[
+                        ofp.action.push_vlan(ethertype=0x8100),
+                        ofp.action.set_field(ofp.oxm.vlan_vid(ofp.OFPVID_PRESENT | s_vlan_id)),
+                        ofp.action.set_field(ofp.oxm.vlan_pcp(0)),
+                        ofp.action.output(port=olt_port)]),
+            ],
+            buffer_id=ofp.OFP_NO_BUFFER,
+            priority=1000)
 
-    self.controller.message_send(request)
-    do_barrier(self.controller)
-    verify_no_errors(self.controller)
-    self.cookie += 1
+        self.controller.message_send(request)
+        do_barrier(self.controller)
+        verify_no_errors(self.controller)
+        self.cookie += 1
 
-    # strip outer vlan (s-vlan) for downstream
-    match = ofp.match()
-    match.oxm_list.append(ofp.oxm.in_port(olt_port))
-    match.oxm_list.append(ofp.oxm.vlan_vid(ofp.OFPVID_PRESENT | s_vlan_id))
-    match.oxm_list.append(ofp.oxm.vlan_pcp(0))
-    request = ofp.message.flow_add(
-        table_id=test_param_get("table", 0),
-        cookie=self.cookie,
-        match=match,
-        instructions=[
-            ofp.instruction.apply_actions(
-                actions=[ofp.action.pop_vlan()]),
-            ofp.instruction.goto_table(1)],
-        buffer_id=ofp.OFP_NO_BUFFER,
-        priority=1000)
+        # strip outer vlan (s-vlan) for downstream
+        match = ofp.match()
+        match.oxm_list.append(ofp.oxm.in_port(olt_port))
+        match.oxm_list.append(ofp.oxm.vlan_vid(ofp.OFPVID_PRESENT | s_vlan_id))
+        match.oxm_list.append(ofp.oxm.vlan_pcp(0))
+        request = ofp.message.flow_add(
+            table_id=test_param_get("table", 0),
+            cookie=self.cookie,
+            match=match,
+            instructions=[
+                ofp.instruction.apply_actions(
+                    actions=[ofp.action.pop_vlan()]),
+                ofp.instruction.goto_table(1)],
+            buffer_id=ofp.OFP_NO_BUFFER,
+            priority=1000)
 
-    self.controller.message_send(request)
-    do_barrier(self.controller)
-    verify_no_errors(self.controller)
+        self.controller.message_send(request)
+        do_barrier(self.controller)
+        verify_no_errors(self.controller)
 
-    # rewrite inner vlan (c-vlan) to default (0) for downstream
-    match = ofp.match()
-    match.oxm_list.append(ofp.oxm.in_port(olt_port))
-    match.oxm_list.append(ofp.oxm.vlan_vid(ofp.OFPVID_PRESENT | c_vlan_id))
-    match.oxm_list.append(ofp.oxm.vlan_pcp(0))
-    self.cookie += 1
+        # rewrite inner vlan (c-vlan) to default (0) for downstream
+        match = ofp.match()
+        match.oxm_list.append(ofp.oxm.in_port(olt_port))
+        match.oxm_list.append(ofp.oxm.vlan_vid(ofp.OFPVID_PRESENT | c_vlan_id))
+        match.oxm_list.append(ofp.oxm.vlan_pcp(0))
+        self.cookie += 1
 
-    request = ofp.message.flow_add(
-        table_id=test_param_get("table", 1),
-        cookie=self.cookie,
-        match=match,
-        instructions=[
-            ofp.instruction.apply_actions(
-                actions=[
-                    ofp.action.pop_vlan(),
-                    ofp.action.output(port=onu_port)])
-        ],
-        buffer_id=ofp.OFP_NO_BUFFER,
-        priority=1000)
+        request = ofp.message.flow_add(
+            table_id=test_param_get("table", 1),
+            cookie=self.cookie,
+            match=match,
+            instructions=[
+                ofp.instruction.apply_actions(
+                    actions=[
+                        ofp.action.pop_vlan(),
+                        ofp.action.output(port=onu_port)])
+            ],
+            buffer_id=ofp.OFP_NO_BUFFER,
+            priority=1000)
 
-    self.controller.message_send(request)
-    do_barrier(self.controller)
-    verify_no_errors(self.controller)
+        self.controller.message_send(request)
+        do_barrier(self.controller)
+        verify_no_errors(self.controller)