diff --git a/src/wormhole/_allocator.py b/src/wormhole/_allocator.py
index b671692..0644c55 100644
--- a/src/wormhole/_allocator.py
+++ b/src/wormhole/_allocator.py
@@ -10,7 +10,7 @@ from . import _interfaces
 class Allocator(object):
     _timing = attrib(validator=provides(_interfaces.ITiming))
     m = MethodicalMachine()
-    set_trace = m.setTrace
+    set_trace = getattr(m, "setTrace", lambda self, f: None)
 
     def wire(self, rendezvous_connector, code):
         self._RC = _interfaces.IRendezvousConnector(rendezvous_connector)
diff --git a/src/wormhole/_boss.py b/src/wormhole/_boss.py
index f10c125..74b5f68 100644
--- a/src/wormhole/_boss.py
+++ b/src/wormhole/_boss.py
@@ -39,7 +39,7 @@ class Boss(object):
     _tor_manager = attrib() # TODO: ITorManager or None
     _timing = attrib(validator=provides(_interfaces.ITiming))
     m = MethodicalMachine()
-    set_trace = m.setTrace
+    set_trace = getattr(m, "setTrace", lambda self, f: None)
 
     def __attrs_post_init__(self):
         self._build_workers()
diff --git a/src/wormhole/_code.py b/src/wormhole/_code.py
index 7ff9603..b2a9a20 100644
--- a/src/wormhole/_code.py
+++ b/src/wormhole/_code.py
@@ -13,7 +13,7 @@ def first(outputs):
 class Code(object):
     _timing = attrib(validator=provides(_interfaces.ITiming))
     m = MethodicalMachine()
-    set_trace = m.setTrace
+    set_trace = getattr(m, "setTrace", lambda self, f: None)
 
     def wire(self, boss, allocator, nameplate, key, input):
         self._B = _interfaces.IBoss(boss)
diff --git a/src/wormhole/_input.py b/src/wormhole/_input.py
index dab364f..82158a3 100644
--- a/src/wormhole/_input.py
+++ b/src/wormhole/_input.py
@@ -13,7 +13,7 @@ def first(outputs):
 class Input(object):
     _timing = attrib(validator=provides(_interfaces.ITiming))
     m = MethodicalMachine()
-    set_trace = m.setTrace
+    set_trace = getattr(m, "setTrace", lambda self, f: None)
 
     def __attrs_post_init__(self):
         self._all_nameplates = set()
diff --git a/src/wormhole/_key.py b/src/wormhole/_key.py
index 454808b..67433ec 100644
--- a/src/wormhole/_key.py
+++ b/src/wormhole/_key.py
@@ -64,7 +64,7 @@ class Key(object):
     _side = attrib(validator=instance_of(type(u"")))
     _timing = attrib(validator=provides(_interfaces.ITiming))
     m = MethodicalMachine()
-    set_trace = m.setTrace
+    set_trace = getattr(m, "setTrace", lambda self, f: None)
 
     def __attrs_post_init__(self):
         self._SK = _SortedKey(self._appid, self._versions, self._side,
@@ -113,7 +113,7 @@ class _SortedKey(object):
     _side = attrib(validator=instance_of(type(u"")))
     _timing = attrib(validator=provides(_interfaces.ITiming))
     m = MethodicalMachine()
-    set_trace = m.setTrace
+    set_trace = getattr(m, "setTrace", lambda self, f: None)
 
     def wire(self, boss, mailbox, receive):
         self._B = _interfaces.IBoss(boss)
diff --git a/src/wormhole/_lister.py b/src/wormhole/_lister.py
index dfca877..cd1a560 100644
--- a/src/wormhole/_lister.py
+++ b/src/wormhole/_lister.py
@@ -10,7 +10,7 @@ from . import _interfaces
 class Lister(object):
     _timing = attrib(validator=provides(_interfaces.ITiming))
     m = MethodicalMachine()
-    set_trace = m.setTrace
+    set_trace = getattr(m, "setTrace", lambda self, f: None)
 
     def wire(self, rendezvous_connector, input):
         self._RC = _interfaces.IRendezvousConnector(rendezvous_connector)
diff --git a/src/wormhole/_mailbox.py b/src/wormhole/_mailbox.py
index 3c5413d..3bca6fb 100644
--- a/src/wormhole/_mailbox.py
+++ b/src/wormhole/_mailbox.py
@@ -10,7 +10,7 @@ from . import _interfaces
 class Mailbox(object):
     _side = attrib(validator=instance_of(type(u"")))
     m = MethodicalMachine()
-    set_trace = m.setTrace
+    set_trace = getattr(m, "setTrace", lambda self, f: None)
 
     def __attrs_post_init__(self):
         self._mailbox = None
diff --git a/src/wormhole/_nameplate.py b/src/wormhole/_nameplate.py
index 00f2f7e..8ee8025 100644
--- a/src/wormhole/_nameplate.py
+++ b/src/wormhole/_nameplate.py
@@ -7,7 +7,7 @@ from ._wordlist import PGPWordList
 @implementer(_interfaces.INameplate)
 class Nameplate(object):
     m = MethodicalMachine()
-    set_trace = m.setTrace
+    set_trace = getattr(m, "setTrace", lambda self, f: None)
 
     def __init__(self):
         self._nameplate = None
diff --git a/src/wormhole/_order.py b/src/wormhole/_order.py
index 26671a1..5383a14 100644
--- a/src/wormhole/_order.py
+++ b/src/wormhole/_order.py
@@ -11,7 +11,7 @@ class Order(object):
     _side = attrib(validator=instance_of(type(u"")))
     _timing = attrib(validator=provides(_interfaces.ITiming))
     m = MethodicalMachine()
-    set_trace = m.setTrace
+    set_trace = getattr(m, "setTrace", lambda self, f: None)
 
     def __attrs_post_init__(self):
         self._key = None
diff --git a/src/wormhole/_receive.py b/src/wormhole/_receive.py
index 7a78518..1be5220 100644
--- a/src/wormhole/_receive.py
+++ b/src/wormhole/_receive.py
@@ -12,7 +12,7 @@ class Receive(object):
     _side = attrib(validator=instance_of(type(u"")))
     _timing = attrib(validator=provides(_interfaces.ITiming))
     m = MethodicalMachine()
-    set_trace = m.setTrace
+    set_trace = getattr(m, "setTrace", lambda self, f: None)
 
     def __attrs_post_init__(self):
         self._key = None
diff --git a/src/wormhole/_send.py b/src/wormhole/_send.py
index 3c8c722..762b2fa 100644
--- a/src/wormhole/_send.py
+++ b/src/wormhole/_send.py
@@ -12,7 +12,7 @@ class Send(object):
     _side = attrib(validator=instance_of(type(u"")))
     _timing = attrib(validator=provides(_interfaces.ITiming))
     m = MethodicalMachine()
-    set_trace = m.setTrace
+    set_trace = getattr(m, "setTrace", lambda self, f: None)
 
     def __attrs_post_init__(self):
         self._queue = []
diff --git a/src/wormhole/_terminator.py b/src/wormhole/_terminator.py
index 3a14042..f90f7e5 100644
--- a/src/wormhole/_terminator.py
+++ b/src/wormhole/_terminator.py
@@ -6,7 +6,7 @@ from . import _interfaces
 @implementer(_interfaces.ITerminator)
 class Terminator(object):
     m = MethodicalMachine()
-    set_trace = m.setTrace
+    set_trace = getattr(m, "setTrace", lambda self, f: None)
 
     def __init__(self):
         self._mood = None