diff --git a/IPython/kernel/inprocess/socket.py b/IPython/kernel/inprocess/socket.py
index d654e52..7e0664e 100644
--- a/IPython/kernel/inprocess/socket.py
+++ b/IPython/kernel/inprocess/socket.py
@@ -58,7 +58,7 @@ class DummySocket(HasTraits):
         return self.queue.get_nowait()
 
     def send_multipart(self, msg_parts, flags=0, copy=True, track=False):
-        msg_parts = map(zmq.Message, msg_parts)
+        msg_parts = list(map(zmq.Message, msg_parts))
         self.queue.put_nowait(msg_parts)
         self.message_sent += 1