diff --git a/tracetools_test/tracetools_test/case.py b/tracetools_test/tracetools_test/case.py
index 375e92f..49d6722 100644
--- a/tracetools_test/tracetools_test/case.py
+++ b/tracetools_test/tracetools_test/case.py
@@ -48,7 +48,7 @@ class TraceTestCase(unittest.TestCase):
         events_ros: List[str],
         nodes: List[str],
         base_path: str = '/tmp',
-        events_kernel: List[str] = None,
+        events_kernel: List[str] = [],
         package: str = 'tracetools_test',
     ) -> None:
         """Create a TraceTestCase."""
@@ -70,7 +70,8 @@ class TraceTestCase(unittest.TestCase):
             self._events_ros,
             self._events_kernel,
             self._package,
-            self._nodes)
+            self._nodes,
+        )
 
         print(f'TRACE DIRECTORY: {full_path}')
         self._exit_code = exit_code
diff --git a/tracetools_test/tracetools_test/utils.py b/tracetools_test/tracetools_test/utils.py
index 4e713b9..ea70478 100644
--- a/tracetools_test/tracetools_test/utils.py
+++ b/tracetools_test/tracetools_test/utils.py
@@ -53,13 +53,15 @@ def run_and_trace(
 
     launch_actions = []
     # Add trace action
-    launch_actions.append(Trace(
-        session_name=session_name,
-        append_timestamp=False,
-        base_path=base_path,
-        events_ust=ros_events,
-        events_kernel=kernel_events
-    ))
+    launch_actions.append(
+        Trace(
+            session_name=session_name,
+            append_timestamp=False,
+            base_path=base_path,
+            events_ust=ros_events,
+            events_kernel=kernel_events,
+        )
+    )
     # Add nodes
     for node_name in node_names:
         n = Node(
diff --git a/tracetools_trace/tracetools_trace/tools/lttng_impl.py b/tracetools_trace/tracetools_trace/tools/lttng_impl.py
index 7c593ce..578c4a6 100644
--- a/tracetools_trace/tracetools_trace/tools/lttng_impl.py
+++ b/tracetools_trace/tracetools_trace/tools/lttng_impl.py
@@ -18,6 +18,7 @@ from distutils.version import StrictVersion
 import re
 from typing import List
 from typing import Optional
+from typing import Set
 from typing import Union
 
 import lttng
@@ -50,9 +51,9 @@ def get_version() -> Union[StrictVersion, None]:
 def setup(
     session_name: str,
     base_path: str = DEFAULT_BASE_PATH,
-    ros_events: List[str] = DEFAULT_EVENTS_ROS,
-    kernel_events: List[str] = DEFAULT_EVENTS_KERNEL,
-    context_names: List[str] = DEFAULT_CONTEXT,
+    ros_events: Union[List[str], Set[str]] = DEFAULT_EVENTS_ROS,
+    kernel_events: Union[List[str], Set[str]] = DEFAULT_EVENTS_KERNEL,
+    context_names: Union[List[str], Set[str]] = DEFAULT_CONTEXT,
     channel_name_ust: str = 'ros2',
     channel_name_kernel: str = 'kchan',
 ) -> Optional[str]:
@@ -70,6 +71,14 @@ def setup(
     :param channel_name_kernel: the kernel channel name
     :return: the full path to the trace directory
     """
+    # Convert lists to sets
+    if not isinstance(ros_events, set):
+        ros_events = set(ros_events)
+    if not isinstance(kernel_events, set):
+        kernel_events = set(kernel_events)
+    if not isinstance(context_names, set):
+        context_names = set(context_names)
+
     # Resolve full tracing directory path
     full_path = get_full_session_path(session_name, base_path=base_path)
 
@@ -181,16 +190,16 @@ def destroy(
 
 
 def _create_events(
-    event_names_list: List[str],
+    event_names: Set[str],
 ) -> List[lttng.Event]:
     """
     Create events list from names.
 
-    :param event_names_list: a list of names to create events for
+    :param event_names: a set of names to create events for
     :return: the list of events
     """
     events_list = []
-    for event_name in event_names_list:
+    for event_name in event_names:
         e = lttng.Event()
         e.name = event_name
         e.type = lttng.EVENT_TRACEPOINT
@@ -290,16 +299,16 @@ def _context_name_to_type(
 
 
 def _create_context_list(
-    context_names_list: List[str],
+    context_names: Set[str],
 ) -> List[lttng.EventContext]:
     """
     Create context list from names, and check for errors.
 
-    :param context_names_list: the list of context names
+    :param context_names: the set of context names
     :return: the event context list
     """
     context_list = []
-    for context_name in context_names_list:
+    for context_name in context_names:
         ec = lttng.EventContext()
         context_type = _context_name_to_type(context_name)
         if context_type is not None: