diff --git a/ros2bag/test/resources/empty_bag/metadata.yaml b/ros2bag/test/resources/empty_bag/metadata.yaml
index d8b475bbea..bf90464011 100644
--- a/ros2bag/test/resources/empty_bag/metadata.yaml
+++ b/ros2bag/test/resources/empty_bag/metadata.yaml
@@ -22,4 +22,4 @@ rosbag2_bagfile_information:
         offered_qos_profiles: "- history: 3\n  depth: 0\n  reliability: 1\n  durability: 1\n  deadline:\n    sec: 2147483647\n    nsec: 4294967295\n  lifespan:\n    sec: 10\n    nsec: 0\n  liveliness: 1\n  liveliness_lease_duration:\n    sec: 2147483647\n    nsec: 4294967295\n  avoid_ros_namespace_conventions: false"
       message_count: 0
   compression_format: ""
-  compression_mode: ""
\ No newline at end of file
+  compression_mode: ""
diff --git a/ros2bag/test/test_play_qos_profiles.py b/ros2bag/test/test_play_qos_profiles.py
index f63297779a..b6f719d48d 100644
--- a/ros2bag/test/test_play_qos_profiles.py
+++ b/ros2bag/test/test_play_qos_profiles.py
@@ -60,6 +60,7 @@ def launch_bag_command(self, arguments, **kwargs):
         cls.launch_bag_command = launch_bag_command
 
     def test_qos_simple(self):
+        """Test with a full QoS profile override for a single topic."""
         profile_path = RESOURCES_PATH / 'qos_profile.yaml'
         bag_path = RESOURCES_PATH / 'empty_bag'
         arguments = ['play', '--qos-profile-overrides-path', profile_path.as_posix(),
@@ -71,6 +72,7 @@ def test_qos_simple(self):
         assert not matches, print('ros2bag CLI did not produce the expected output')
 
     def test_qos_incomplete(self):
+        """Test a partially filled QoS profile for a single topic."""
         profile_path = RESOURCES_PATH / 'incomplete_qos_profile.yaml'
         bag_path = RESOURCES_PATH / 'empty_bag'
         arguments = ['play', '--qos-profile-overrides-path', profile_path.as_posix(),
diff --git a/rosbag2_transport/src/rosbag2_transport/rosbag2_transport_python.cpp b/rosbag2_transport/src/rosbag2_transport/rosbag2_transport_python.cpp
index c8cbc6f3a3..0aca3d510d 100644
--- a/rosbag2_transport/src/rosbag2_transport/rosbag2_transport_python.cpp
+++ b/rosbag2_transport/src/rosbag2_transport/rosbag2_transport_python.cpp
@@ -61,15 +61,15 @@ std::unordered_map<std::string, rclcpp::QoS> PyObject_AsTopicQoSMap(PyObject * o
 {
   std::unordered_map<std::string, rclcpp::QoS> topic_qos_overrides{};
   if (PyDict_Check(object)) {
-    PyObject * key = nullptr;
-    PyObject * value = nullptr;
-    Py_ssize_t pos = 0;
+    PyObject * key{nullptr};
+    PyObject * value{nullptr};
+    Py_ssize_t pos{0};
     while (PyDict_Next(object, &pos, &key, &value)) {
       auto topic_name = PyObject_AsStdString(key);
       auto rmw_qos_profile = PyQoSProfile_AsRmwQoSProfile(value);
       auto qos_init = rclcpp::QoSInitialization::from_rmw(*rmw_qos_profile);
       auto qos_profile = rclcpp::QoS(qos_init, *rmw_qos_profile);
-      topic_qos_overrides.insert(std::pair<std::string, rclcpp::QoS>(topic_name, qos_profile));
+      topic_qos_overrides.insert({topic_name, qos_profile});
     }
   } else {
     throw std::runtime_error{"QoS profile overrides object is not a Python dictionary."};
@@ -216,7 +216,7 @@ rosbag2_transport_play(PyObject * Py_UNUSED(self), PyObject * args, PyObject * k
   char * node_prefix;
   size_t read_ahead_queue_size;
   float rate;
-  PyObject * qos_profile_overrides;
+  PyObject * qos_profile_overrides{nullptr};
   if (!PyArg_ParseTupleAndKeywords(
       args, kwargs, "sss|kfO", const_cast<char **>(kwlist),
       &uri,