diff --git a/src/allmydata/introducer/server.py b/src/allmydata/introducer/server.py
index 237c30315..339c5a0ac 100644
--- a/src/allmydata/introducer/server.py
+++ b/src/allmydata/introducer/server.py
@@ -15,6 +15,12 @@ from past.builtins import long
 from six import ensure_text
 
 import time, os.path, textwrap
+
+try:
+    from typing import Any, Dict, Union
+except ImportError:
+    pass
+
 from zope.interface import implementer
 from twisted.application import service
 from twisted.internet import defer
@@ -147,10 +153,12 @@ class IntroducerService(service.MultiService, Referenceable):
     name = "introducer"
     # v1 is the original protocol, added in 1.0 (but only advertised starting
     # in 1.3), removed in 1.12. v2 is the new signed protocol, added in 1.10
-    VERSION = { #"http://allmydata.org/tahoe/protocols/introducer/v1": { },
+    # TODO: reconcile bytes/str for keys
+    VERSION = {
+                #"http://allmydata.org/tahoe/protocols/introducer/v1": { },
                 b"http://allmydata.org/tahoe/protocols/introducer/v2": { },
                 b"application-version": allmydata.__full_version__.encode("utf-8"),
-                }
+                }  # type: Dict[Union[bytes, str], Any]
 
     def __init__(self):
         service.MultiService.__init__(self)