diff --git a/electrum/interface.py b/electrum/interface.py
index 45a05576a..19581bf94 100644
--- a/electrum/interface.py
+++ b/electrum/interface.py
@@ -32,6 +32,7 @@ import traceback
 import aiorpcx
 import asyncio
 import concurrent.futures
+from aiorpcx import ClientSession, Notification
 
 import requests
 
@@ -43,8 +44,29 @@ from . import util
 from . import x509
 from . import pem
 from .version import ELECTRUM_VERSION, PROTOCOL_VERSION
-from .util import NotificationSession
 from . import blockchain
+from .blockchain import deserialize_header
+
+
+class NotificationSession(ClientSession):
+
+    def __init__(self, scripthash, header, *args, **kwargs):
+        super(NotificationSession, self).__init__(*args, **kwargs)
+        self.scripthash = scripthash
+        self.header = header
+
+    @aiosafe
+    async def handle_request(self, request):
+        if isinstance(request, Notification):
+            if request.method == 'blockchain.scripthash.subscribe' and self.scripthash is not None:
+                args = request.args
+                await self.scripthash.put((args[0], args[1]))
+            elif request.method == 'blockchain.headers.subscribe' and self.header is not None:
+                deser = deserialize_header(bfh(request.args[0]['hex']), request.args[0]['height'])
+                await self.header.put(deser)
+            else:
+                assert False, request.method
+
 
 class Interface(PrintError):
 
diff --git a/electrum/synchronizer.py b/electrum/synchronizer.py
index eba1ec7f0..3fe16a251 100644
--- a/electrum/synchronizer.py
+++ b/electrum/synchronizer.py
@@ -32,7 +32,7 @@ import concurrent.futures
 
 # from .bitcoin import Hash, hash_encode
 from .transaction import Transaction
-from .util import ThreadJob, bh2u, PrintError, aiosafe, bfh, NotificationSession
+from .util import ThreadJob, bh2u, PrintError, aiosafe, bfh
 from .bitcoin import address_to_scripthash
 from .version import ELECTRUM_VERSION, PROTOCOL_VERSION
 
diff --git a/electrum/util.py b/electrum/util.py
index ec4d44342..4a3629cd4 100644
--- a/electrum/util.py
+++ b/electrum/util.py
@@ -38,7 +38,6 @@ from locale import localeconv
 from .i18n import _
 
 
-from aiorpcx import ClientSession, Notification
 import urllib.request, urllib.parse, urllib.error
 import queue
 
@@ -948,24 +947,3 @@ VerifiedTxInfo = NamedTuple("VerifiedTxInfo", [("height", int),
                                                ("timestamp", int),
                                                ("txpos", int),
                                                ("header_hash", str)])
-
-from .blockchain import deserialize_header
-
-class NotificationSession(ClientSession):
-
-    def __init__(self, scripthash, header, *args, **kwargs):
-        super(NotificationSession, self).__init__(*args, **kwargs)
-        self.scripthash = scripthash
-        self.header = header
-
-    @aiosafe
-    async def handle_request(self, request):
-        if isinstance(request, Notification):
-            if request.method == 'blockchain.scripthash.subscribe' and self.scripthash is not None:
-                args = request.args
-                await self.scripthash.put((args[0], args[1]))
-            elif request.method == 'blockchain.headers.subscribe' and self.header is not None:
-                deser = deserialize_header(bfh(request.args[0]['hex']), request.args[0]['height'])
-                await self.header.put(deser)
-            else:
-                assert False, request.method