diff --git a/trezorlib/client.py b/trezorlib/client.py
index 0b5806c..950d8f9 100644
--- a/trezorlib/client.py
+++ b/trezorlib/client.py
@@ -405,9 +405,8 @@ class DebugLinkMixin(object):
                                     "Expected %s, got %s" % (pprint(expected), pprint(msg)))
 
             for field, value in expected.__dict__.items():
-                if getattr(expected, field) is None:
+                if value is None or value == []:
                     continue
-                print("EXPECTED", getattr(expected, field), getattr(msg, field), field, value)
                 if getattr(msg, field) != value:
                     raise CallException(proto.FailureType.UnexpectedMessage,
                                         "Expected %s, got %s" % (pprint(expected), pprint(msg)))
diff --git a/trezorlib/protobuf.py b/trezorlib/protobuf.py
index d367556..096fb66 100644
--- a/trezorlib/protobuf.py
+++ b/trezorlib/protobuf.py
@@ -102,7 +102,12 @@ class MessageType:
                 self.__dict__ == rhs.__dict__)
 
     def __repr__(self):
-        return '<%s: %s>' % (self.__class__.__name__, self.__dict__)
+        d = {}
+        for key, value in self.__dict__.items():
+            if value is None or value == []:
+                continue
+            d[key] = value
+        return '<%s: %s>' % (self.__class__.__name__, d)
 
     def __iter__(self):
         return self.__dict__.__iter__()