diff --git a/azure-pipelines.yml b/azure-pipelines.yml
index 7d4105a..0c8c9c7 100644
--- a/azure-pipelines.yml
+++ b/azure-pipelines.yml
@@ -2,7 +2,7 @@
 trigger:
 - master
 
-name: '1.1.16'
+name: '1.1.17'
 
 jobs:
 
diff --git a/chapter10/__init__.py b/chapter10/__init__.py
index 764ba28..b242e3f 100755
--- a/chapter10/__init__.py
+++ b/chapter10/__init__.py
@@ -1,3 +1,3 @@
 from .c10 import C10, TYPES
 from .packet import Packet, InvalidPacket
-version = '1.1.15'
+version = '1.1.17'
diff --git a/chapter10/packet.py b/chapter10/packet.py
index 51004a9..de768eb 100755
--- a/chapter10/packet.py
+++ b/chapter10/packet.py
@@ -216,7 +216,7 @@ def __len__(self):
             return len(self._messages)
         if hasattr(self, 'count'):
             return self.count
-        elif hasattr(self, 'Message') and self.Message.length:
+        elif getattr(self, 'Message', None) and self.Message.length:
             msg_size = self.Message.length
             if getattr(self.Message, 'FORMAT', None):
                 msg_size += self.Message.FORMAT.calcsize() // 8
diff --git a/pyproject.toml b/pyproject.toml
index 1671c4c..05f7aee 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "pychapter10"
-version = "0.1.16"
+version = "0.1.17"
 description = "A parser library for the IRIG 106 Chapter 10 data format."
 authors = [
     {name = "Micah Ferrill", email = "ferrillm@avtest.com"},
diff --git a/tests/unit/test_pcm.py b/tests/unit/test_pcm.py
index cedab51..c1c606a 100644
--- a/tests/unit/test_pcm.py
+++ b/tests/unit/test_pcm.py
@@ -35,3 +35,8 @@ def test_packed(packet):
 def test_throughput(throughput):
     with pytest.raises(StopIteration):
         next(throughput)
+
+
+def test_throughput_len(throughput):
+    with pytest.raises(TypeError):
+        len(throughput)
\ No newline at end of file