default middle_module to 'msg'

Signed-off-by: David Hodo <[email protected]>

Author: David Hodo

ros2topic/ros2topic/api/__init__.py

@@ -58,7 +58,9 @@ def import_message_type(topic_name, message_type):
     # TODO(dirk-thomas) this logic should come from a rosidl related package
     try:
         package_name, middle_module, message_name = message_type.split('/')
-        if not package_name or not middle_module or not message_name:
+        if not middle_module:
+            middle_module = 'msg'
+        if not package_name  or not message_name:
             raise ValueError()
     except ValueError:
         raise RuntimeError('The passed message type is invalid')