diff --git a/rosidl_runtime_py/convert.py b/rosidl_runtime_py/convert.py
index ae456be..1a45e89 100644
--- a/rosidl_runtime_py/convert.py
+++ b/rosidl_runtime_py/convert.py
@@ -211,7 +211,11 @@ def _convert_value(
             value = '<string length: <{0}>>'.format(len(value))
         elif truncate_length is not None and len(value) > truncate_length:
             value = value[:truncate_length] + '...'
-    elif isinstance(value, (array.array, numpy.ndarray)) and not no_arr and truncate_length is None:
+    elif (
+        isinstance(value, (array.array, numpy.ndarray))
+        and not no_arr
+        and truncate_length is None
+    ):
         value = value.tolist()
     elif isinstance(value, (list, tuple, array.array, numpy.ndarray)):
         # Since arrays and ndarrays can't contain mixed types convert to list