more flake8 fixes, in wormhole.py and _interfaces.py

src/wormhole/_interfaces.py

@@ -434,15 +434,26 @@ class IInputHelper(Interface):
 class IJournal(Interface):  # TODO: this needs to be public
     pass
 
+
 class IDilator(Interface):
     pass
+
+
 class IDilationManager(Interface):
     pass
+
+
 class IDilationConnector(Interface):
     pass
+
+
 class ISubChannel(Interface):
     pass
+
+
 class IInbound(Interface):
     pass
+
+
 class IOutbound(Interface):
     pass