diff --git a/openhands/events/action/message.py b/openhands/events/action/message.py
index d865264196..f4f1c2ae54 100644
--- a/openhands/events/action/message.py
+++ b/openhands/events/action/message.py
@@ -17,12 +17,12 @@ class MessageAction(Action):
         return self.content
 
     @property
-    def images_urls(self):
+    def images_urls(self) -> list[str] | None:
         # Deprecated alias for backward compatibility
         return self.image_urls
 
     @images_urls.setter
-    def images_urls(self, value):
+    def images_urls(self, value: list[str] | None) -> None:
         self.image_urls = value
 
     def __str__(self) -> str:
diff --git a/openhands/events/event.py b/openhands/events/event.py
index 8481a16393..aaddc6daf2 100644
--- a/openhands/events/event.py
+++ b/openhands/events/event.py
@@ -39,19 +39,23 @@ class Event:
     @property
     def message(self) -> str | None:
         if hasattr(self, '_message'):
-            return self._message  # type: ignore[attr-defined]
+            msg = getattr(self, '_message')
+            return str(msg) if msg is not None else None
         return ''
 
     @property
     def id(self) -> int:
         if hasattr(self, '_id'):
-            return self._id  # type: ignore[attr-defined]
+            id_val = getattr(self, '_id')
+            return int(id_val) if id_val is not None else Event.INVALID_ID
         return Event.INVALID_ID
 
     @property
-    def timestamp(self):
+    def timestamp(self) -> str | None:
         if hasattr(self, '_timestamp') and isinstance(self._timestamp, str):
-            return self._timestamp
+            ts = getattr(self, '_timestamp')
+            return str(ts) if ts is not None else None
+        return None
 
     @timestamp.setter
     def timestamp(self, value: datetime) -> None:
@@ -61,22 +65,25 @@ class Event:
     @property
     def source(self) -> EventSource | None:
         if hasattr(self, '_source'):
-            return self._source  # type: ignore[attr-defined]
+            src = getattr(self, '_source')
+            return EventSource(src) if src is not None else None
         return None
 
     @property
     def cause(self) -> int | None:
         if hasattr(self, '_cause'):
-            return self._cause  # type: ignore[attr-defined]
+            cause_val = getattr(self, '_cause')
+            return int(cause_val) if cause_val is not None else None
         return None
 
     @property
-    def timeout(self) -> int | None:
+    def timeout(self) -> float | None:
         if hasattr(self, '_timeout'):
-            return self._timeout  # type: ignore[attr-defined]
+            timeout_val = getattr(self, '_timeout')
+            return float(timeout_val) if timeout_val is not None else None
         return None
 
-    def set_hard_timeout(self, value: int | None, blocking: bool = True) -> None:
+    def set_hard_timeout(self, value: float | None, blocking: bool = True) -> None:
         """Set the timeout for the event.
 
         NOTE, this is a hard timeout, meaning that the event will be blocked
@@ -100,7 +107,8 @@ class Event:
     @property
     def llm_metrics(self) -> Metrics | None:
         if hasattr(self, '_llm_metrics'):
-            return self._llm_metrics  # type: ignore[attr-defined]
+            metrics = getattr(self, '_llm_metrics')
+            return metrics if isinstance(metrics, Metrics) else None
         return None
 
     @llm_metrics.setter
@@ -111,7 +119,8 @@ class Event:
     @property
     def tool_call_metadata(self) -> ToolCallMetadata | None:
         if hasattr(self, '_tool_call_metadata'):
-            return self._tool_call_metadata  # type: ignore[attr-defined]
+            metadata = getattr(self, '_tool_call_metadata')
+            return metadata if isinstance(metadata, ToolCallMetadata) else None
         return None
 
     @tool_call_metadata.setter
diff --git a/openhands/events/observation/browse.py b/openhands/events/observation/browse.py
index c8a4c2cb62..da268a16e8 100644
--- a/openhands/events/observation/browse.py
+++ b/openhands/events/observation/browse.py
@@ -1,4 +1,5 @@
 from dataclasses import dataclass, field
+from typing import Any
 
 from browsergym.utils.obs import flatten_axtree_to_str
 
@@ -16,13 +17,17 @@ class BrowserOutputObservation(Observation):
     set_of_marks: str = field(default='', repr=False)  # don't show in repr
     error: bool = False
     observation: str = ObservationType.BROWSE
-    goal_image_urls: list = field(default_factory=list)
+    goal_image_urls: list[str] = field(default_factory=list)
     # do not include in the memory
-    open_pages_urls: list = field(default_factory=list)
+    open_pages_urls: list[str] = field(default_factory=list)
     active_page_index: int = -1
-    dom_object: dict = field(default_factory=dict, repr=False)  # don't show in repr
-    axtree_object: dict = field(default_factory=dict, repr=False)  # don't show in repr
-    extra_element_properties: dict = field(
+    dom_object: dict[str, Any] = field(
+        default_factory=dict, repr=False
+    )  # don't show in repr
+    axtree_object: dict[str, Any] = field(
+        default_factory=dict, repr=False
+    )  # don't show in repr
+    extra_element_properties: dict[str, Any] = field(
         default_factory=dict, repr=False
     )  # don't show in repr
     last_browser_action: str = ''
@@ -102,4 +107,4 @@ class BrowserOutputObservation(Observation):
             skip_generic=False,
             filter_visible_only=filter_visible_only,
         )
-        return cur_axtree_txt
+        return str(cur_axtree_txt)
diff --git a/openhands/events/observation/commands.py b/openhands/events/observation/commands.py
index edddb250cd..db0c6ab9ee 100644
--- a/openhands/events/observation/commands.py
+++ b/openhands/events/observation/commands.py
@@ -2,7 +2,7 @@ import json
 import re
 import traceback
 from dataclasses import dataclass, field
-from typing import Self
+from typing import Any, Self
 
 from pydantic import BaseModel
 
@@ -105,10 +105,10 @@ class CmdOutputObservation(Observation):
         content: str,
         command: str,
         observation: str = ObservationType.RUN,
-        metadata: dict | CmdOutputMetadata | None = None,
+        metadata: dict[str, Any] | CmdOutputMetadata | None = None,
         hidden: bool = False,
-        **kwargs,
-    ):
+        **kwargs: Any,
+    ) -> None:
         super().__init__(content)
         self.command = command
         self.observation = observation
diff --git a/openhands/events/serialization/action.py b/openhands/events/serialization/action.py
index 462e5dd250..587a84a20b 100644
--- a/openhands/events/serialization/action.py
+++ b/openhands/events/serialization/action.py
@@ -1,3 +1,5 @@
+import re
+from typing import Any
 from openhands.core.exceptions import LLMMalformedActionError
 from openhands.events.action.action import Action
 from openhands.events.action.agent import (
@@ -42,7 +44,7 @@ actions = (
 ACTION_TYPE_TO_CLASS = {action_class.action: action_class for action_class in actions}  # type: ignore[attr-defined]
 
 
-def handle_action_deprecated_args(args: dict) -> dict:
+def handle_action_deprecated_args(args: dict[str, Any]) -> dict[str, Any]:
     # keep_prompt has been deprecated in https://github.com/All-Hands-AI/OpenHands/pull/4881
     if 'keep_prompt' in args:
         args.pop('keep_prompt')
@@ -126,4 +128,5 @@ def action_from_dict(action: dict) -> Action:
         raise LLMMalformedActionError(
             f'action={action} has the wrong arguments: {str(e)}'
         )
+    assert isinstance(decoded_action, Action)
     return decoded_action
diff --git a/openhands/events/serialization/event.py b/openhands/events/serialization/event.py
index ac0d9fb6c4..fdc91fbde6 100644
--- a/openhands/events/serialization/event.py
+++ b/openhands/events/serialization/event.py
@@ -1,6 +1,7 @@
 from dataclasses import asdict
 from datetime import datetime
 from enum import Enum
+from typing import Any
 
 from pydantic import BaseModel
 
@@ -48,14 +49,14 @@ DELETE_FROM_TRAJECTORY_EXTRAS_AND_SCREENSHOTS = DELETE_FROM_TRAJECTORY_EXTRAS |
 }
 
 
-def event_from_dict(data) -> 'Event':
+def event_from_dict(data: dict[str, Any]) -> 'Event':
     evt: Event
     if 'action' in data:
         evt = action_from_dict(data)
     elif 'observation' in data:
         evt = observation_from_dict(data)
     else:
-        raise ValueError('Unknown event type: ' + data)
+        raise ValueError(f'Unknown event type: {data}')
     for key in UNDERSCORE_KEYS:
         if key in data:
             value = data[key]
diff --git a/openhands/events/serialization/observation.py b/openhands/events/serialization/observation.py
index 84bb20d4a2..6785468da3 100644
--- a/openhands/events/serialization/observation.py
+++ b/openhands/events/serialization/observation.py
@@ -1,4 +1,5 @@
 import copy
+from typing import Any
 
 from openhands.events.event import RecallType
 from openhands.events.observation.agent import (
@@ -53,8 +54,8 @@ OBSERVATION_TYPE_TO_CLASS = {
 
 
 def _update_cmd_output_metadata(
-    metadata: dict | CmdOutputMetadata | None, **kwargs
-) -> dict | CmdOutputMetadata:
+    metadata: dict[str, Any] | CmdOutputMetadata | None, **kwargs: Any
+) -> dict[str, Any] | CmdOutputMetadata:
     """Update the metadata of a CmdOutputObservation.
 
     If metadata is None, create a new CmdOutputMetadata instance.
@@ -128,4 +129,6 @@ def observation_from_dict(observation: dict) -> Observation:
                 for item in extras['microagent_knowledge']
             ]
 
-    return observation_class(content=content, **extras)
+    obs = observation_class(content=content, **extras)
+    assert isinstance(obs, Observation)
+    return obs
diff --git a/openhands/events/serialization/utils.py b/openhands/events/serialization/utils.py
index de448e0142..c2eac8a996 100644
--- a/openhands/events/serialization/utils.py
+++ b/openhands/events/serialization/utils.py
@@ -1,4 +1,4 @@
-def remove_fields(obj, fields: set[str]):
+def remove_fields(obj: dict | list | tuple, fields: set[str]) -> None:
     """Remove fields from an object.
 
     Parameters:
@@ -14,7 +14,7 @@ def remove_fields(obj, fields: set[str]):
     elif isinstance(obj, (list, tuple)):
         for item in obj:
             remove_fields(item, fields)
-    elif hasattr(obj, '__dataclass_fields__'):
+    if hasattr(obj, '__dataclass_fields__'):
         raise ValueError(
             'Object must not contain dataclass, consider converting to dict first'
         )
diff --git a/openhands/events/stream.py b/openhands/events/stream.py
index a107c726e1..ce562a2817 100644
--- a/openhands/events/stream.py
+++ b/openhands/events/stream.py
@@ -5,7 +5,7 @@ from concurrent.futures import ThreadPoolExecutor
 from datetime import datetime
 from enum import Enum
 from functools import partial
-from typing import Callable, Iterable
+from typing import Any, AsyncIterator, Callable, Iterable
 
 from openhands.core.logger import openhands_logger as logger
 from openhands.events.event import Event, EventSource
@@ -43,18 +43,21 @@ async def session_exists(
 
 
 class AsyncEventStreamWrapper:
-    def __init__(self, event_stream, *args, **kwargs):
+    def __init__(self, event_stream: 'EventStream', *args: Any, **kwargs: Any) -> None:
         self.event_stream = event_stream
         self.args = args
         self.kwargs = kwargs
 
-    async def __aiter__(self):
+    async def __aiter__(self) -> AsyncIterator[Event]:
         loop = asyncio.get_running_loop()
 
         # Create an async generator that yields events
         for event in self.event_stream.get_events(*self.args, **self.kwargs):
             # Run the blocking get_events() in a thread pool
-            yield await loop.run_in_executor(None, lambda e=event: e)  # type: ignore
+            def get_event(e: Event = event) -> Event:
+                return e
+
+            yield await loop.run_in_executor(None, get_event)
 
 
 class EventStream:
@@ -121,14 +124,14 @@ class EventStream:
             if id >= self._cur_id:
                 self._cur_id = id + 1
 
-    def _init_thread_loop(self, subscriber_id: str, callback_id: str):
+    def _init_thread_loop(self, subscriber_id: str, callback_id: str) -> None:
         loop = asyncio.new_event_loop()
         asyncio.set_event_loop(loop)
         if subscriber_id not in self._thread_loops:
             self._thread_loops[subscriber_id] = {}
         self._thread_loops[subscriber_id][callback_id] = loop
 
-    def close(self):
+    def close(self) -> None:
         self._stop_flag.set()
         if self._queue_thread.is_alive():
             self._queue_thread.join()
@@ -143,7 +146,7 @@ class EventStream:
         while not self._queue.empty():
             self._queue.get()
 
-    def _clean_up_subscriber(self, subscriber_id: str, callback_id: str):
+    def _clean_up_subscriber(self, subscriber_id: str, callback_id: str) -> None:
         if subscriber_id not in self._subscribers:
             logger.warning(f'Subscriber not found during cleanup: {subscriber_id}')
             return
@@ -191,7 +194,7 @@ class EventStream:
         end_id: int | None = None,
         reverse: bool = False,
         filter_out_type: tuple[type[Event], ...] | None = None,
-        filter_hidden=False,
+        filter_hidden: bool = False,
     ) -> Iterable[Event]:
         """
         Retrieve events from the event stream, optionally filtering out events of a given type
@@ -208,7 +211,7 @@ class EventStream:
             Events from the stream that match the criteria.
         """
 
-        def should_filter(event: Event):
+        def should_filter(event: Event) -> bool:
             if filter_hidden and hasattr(event, 'hidden') and event.hidden:
                 return True
             if filter_out_type is not None and isinstance(event, filter_out_type):
@@ -263,8 +266,11 @@ class EventStream:
         return self._cur_id - 1
 
     def subscribe(
-        self, subscriber_id: EventStreamSubscriber, callback: Callable, callback_id: str
-    ):
+        self,
+        subscriber_id: EventStreamSubscriber,
+        callback: Callable[[Event], None],
+        callback_id: str,
+    ) -> None:
         initializer = partial(self._init_thread_loop, subscriber_id, callback_id)
         pool = ThreadPoolExecutor(max_workers=1, initializer=initializer)
         if subscriber_id not in self._subscribers:
@@ -279,7 +285,9 @@ class EventStream:
         self._subscribers[subscriber_id][callback_id] = callback
         self._thread_pools[subscriber_id][callback_id] = pool
 
-    def unsubscribe(self, subscriber_id: EventStreamSubscriber, callback_id: str):
+    def unsubscribe(
+        self, subscriber_id: EventStreamSubscriber, callback_id: str
+    ) -> None:
         if subscriber_id not in self._subscribers:
             logger.warning(f'Subscriber not found during unsubscribe: {subscriber_id}')
             return
@@ -290,8 +298,8 @@ class EventStream:
 
         self._clean_up_subscriber(subscriber_id, callback_id)
 
-    def add_event(self, event: Event, source: EventSource):
-        if hasattr(event, '_id') and event.id is not None:
+    def add_event(self, event: Event, source: EventSource) -> None:
+        if event.id != Event.INVALID_ID:
             raise ValueError(
                 f'Event already has an ID:{event.id}. It was probably added back to the EventStream from inside a handler, triggering a loop.'
             )
@@ -310,13 +318,13 @@ class EventStream:
             )
         self._queue.put(event)
 
-    def set_secrets(self, secrets: dict[str, str]):
+    def set_secrets(self, secrets: dict[str, str]) -> None:
         self.secrets = secrets.copy()
 
-    def update_secrets(self, secrets: dict[str, str]):
+    def update_secrets(self, secrets: dict[str, str]) -> None:
         self.secrets.update(secrets)
 
-    def _replace_secrets(self, data: dict) -> dict:
+    def _replace_secrets(self, data: dict[str, Any]) -> dict[str, Any]:
         for key in data:
             if isinstance(data[key], dict):
                 data[key] = self._replace_secrets(data[key])
@@ -325,7 +333,7 @@ class EventStream:
                     data[key] = data[key].replace(secret, '<secret_hidden>')
         return data
 
-    def _run_queue_loop(self):
+    def _run_queue_loop(self) -> None:
         self._queue_loop = asyncio.new_event_loop()
         asyncio.set_event_loop(self._queue_loop)
         try:
@@ -333,7 +341,7 @@ class EventStream:
         finally:
             self._queue_loop.close()
 
-    async def _process_queue(self):
+    async def _process_queue(self) -> None:
         while should_continue() and not self._stop_flag.is_set():
             event = None
             try:
@@ -350,8 +358,10 @@ class EventStream:
                     future = pool.submit(callback, event)
                     future.add_done_callback(self._make_error_handler(callback_id, key))
 
-    def _make_error_handler(self, callback_id: str, subscriber_id: str):
-        def _handle_callback_error(fut):
+    def _make_error_handler(
+        self, callback_id: str, subscriber_id: str
+    ) -> Callable[[Any], None]:
+        def _handle_callback_error(fut: Any) -> None:
             try:
                 # This will raise any exception that occurred during callback execution
                 fut.result()
@@ -364,14 +374,14 @@ class EventStream:
 
         return _handle_callback_error
 
-    def filtered_events_by_source(self, source: EventSource):
+    def filtered_events_by_source(self, source: EventSource) -> Iterable[Event]:
         for event in self.get_events():
             if event.source == source:
                 yield event
 
     def _should_filter_event(
         self,
-        event,
+        event: Event,
         query: str | None = None,
         event_types: tuple[type[Event], ...] | None = None,
         source: str | None = None,
@@ -394,13 +404,14 @@ class EventStream:
         if event_types and not isinstance(event, event_types):
             return True
 
-        if source and not event.source.value == source:
+        if source:
+            if event.source is None or event.source.value != source:
+                return True
+
+        if start_date and event.timestamp is not None and event.timestamp < start_date:
             return True
 
-        if start_date and event.timestamp < start_date:
-            return True
-
-        if end_date and event.timestamp > end_date:
+        if end_date and event.timestamp is not None and event.timestamp > end_date:
             return True
 
         # Text search in event content if query provided
@@ -422,7 +433,7 @@ class EventStream:
         start_id: int = 0,
         limit: int = 100,
         reverse: bool = False,
-    ) -> list[type[Event]]:
+    ) -> list[Event]:
         """Get matching events from the event stream based on filters.
 
         Args:
diff --git a/openhands/security/analyzer.py b/openhands/security/analyzer.py
index 9ce1c11255..ffabca14ff 100644
--- a/openhands/security/analyzer.py
+++ b/openhands/security/analyzer.py
@@ -1,3 +1,4 @@
+import asyncio
 from typing import Any
 from uuid import uuid4
 
@@ -19,8 +20,12 @@ class SecurityAnalyzer:
             event_stream: The event stream to listen for events.
         """
         self.event_stream = event_stream
+
+        def sync_on_event(event: Event) -> None:
+            asyncio.create_task(self.on_event(event))
+
         self.event_stream.subscribe(
-            EventStreamSubscriber.SECURITY_ANALYZER, self.on_event, str(uuid4())
+            EventStreamSubscriber.SECURITY_ANALYZER, sync_on_event, str(uuid4())
         )
 
     async def on_event(self, event: Event) -> None:
diff --git a/openhands/server/listen_socket.py b/openhands/server/listen_socket.py
index c09771c0c0..491c0aa44c 100644
--- a/openhands/server/listen_socket.py
+++ b/openhands/server/listen_socket.py
@@ -58,6 +58,8 @@ async def connect(connection_id: str, environ):
         f'Connected to conversation {conversation_id} with connection_id {connection_id}. Replaying event stream...'
     )
     agent_state_changed = None
+    if event_stream is None:
+        raise ConnectionRefusedError('Failed to join conversation')
     async_stream = AsyncEventStreamWrapper(event_stream, latest_event_id + 1)
     async for event in async_stream:
         logger.info(f'oh_event: {event.__class__.__name__}')
diff --git a/tests/runtime/test_bash.py b/tests/runtime/test_bash.py
index 48dae5c422..d5911c89fc 100644
--- a/tests/runtime/test_bash.py
+++ b/tests/runtime/test_bash.py
@@ -52,7 +52,7 @@ def test_bash_server(temp_dir, runtime_cls, run_as_openhands):
         assert obs.exit_code == -1
         assert 'Serving HTTP on 0.0.0.0 port 8080' in obs.content
         assert (
-            "[The command timed out after 1 seconds. You may wait longer to see additional output by sending empty command '', send other commands to interact with the current process, or send keys to interrupt/kill the command.]"
+            "[The command timed out after 1.0 seconds. You may wait longer to see additional output by sending empty command '', send other commands to interact with the current process, or send keys to interrupt/kill the command.]"
             in obs.metadata.suffix
         )
 
diff --git a/tests/unit/test_event_stream.py b/tests/unit/test_event_stream.py
index 0fe25228e3..e8b91c7f7d 100644
--- a/tests/unit/test_event_stream.py
+++ b/tests/unit/test_event_stream.py
@@ -24,6 +24,7 @@ from openhands.events.observation.files import (
     FileReadObservation,
     FileWriteObservation,
 )
+from openhands.events.serialization.event import event_to_dict
 from openhands.storage import get_file_store
 from openhands.storage.locations import get_conversation_event_filename
 
@@ -157,6 +158,31 @@ def test_get_matching_events_source_filter(temp_dir: str):
         and events[0].source == EventSource.ENVIRONMENT
     )
 
+    # Test that source comparison works correctly with None source
+    null_source_event = NullObservation('test4')
+    event_stream.add_event(null_source_event, EventSource.AGENT)
+    event = event_stream.get_event(event_stream.get_latest_event_id())
+    event._source = None  # type: ignore
+
+    # Update the serialized version
+    data = event_to_dict(event)
+    event_stream.file_store.write(
+        event_stream._get_filename_for_id(event.id, event_stream.user_id),
+        json.dumps(data),
+    )
+
+    # Verify that source comparison works correctly
+    assert event_stream._should_filter_event(
+        event, source='agent'
+    )  # Should filter out None source events
+    assert not event_stream._should_filter_event(
+        event, source=None
+    )  # Should not filter out when source filter is None
+
+    # Filter by AGENT source again
+    events = event_stream.get_matching_events(source='agent')
+    assert len(events) == 2  # Should not include the None source event
+
 
 def test_get_matching_events_pagination(temp_dir: str):
     file_store = get_file_store('local', temp_dir)
@@ -210,7 +236,7 @@ def test_memory_usage_file_operations(temp_dir: str):
     """
 
     def get_memory_mb():
-        """Get current memory usage in MB"""
+        """Get current memory usage in MB."""
         process = psutil.Process(os.getpid())
         return process.memory_info().rss / 1024 / 1024
 
diff --git a/tests/unit/test_prompt_caching.py b/tests/unit/test_prompt_caching.py
index 2e149c1a37..193363fd4b 100644
--- a/tests/unit/test_prompt_caching.py
+++ b/tests/unit/test_prompt_caching.py
@@ -61,13 +61,13 @@ def test_get_messages(codeact_agent: CodeActAgent):
     message_action_1._source = 'user'
     history.append(message_action_1)
     message_action_2 = MessageAction('Sure!')
-    message_action_2._source = 'assistant'
+    message_action_2._source = 'agent'
     history.append(message_action_2)
     message_action_3 = MessageAction('Hello, agent!')
     message_action_3._source = 'user'
     history.append(message_action_3)
     message_action_4 = MessageAction('Hello, user!')
-    message_action_4._source = 'assistant'
+    message_action_4._source = 'agent'
     history.append(message_action_4)
     message_action_5 = MessageAction('Laaaaaaaast!')
     message_action_5._source = 'user'
@@ -106,7 +106,7 @@ def test_get_messages_prompt_caching(codeact_agent: CodeActAgent):
         message_action_user._source = 'user'
         history.append(message_action_user)
         message_action_agent = MessageAction(f'Agent message {i}')
-        message_action_agent._source = 'assistant'
+        message_action_agent._source = 'agent'
         history.append(message_action_agent)
 
     codeact_agent.reset()
diff --git a/tests/unit/test_security.py b/tests/unit/test_security.py
index d8e95e26ea..fc66e59caf 100644
--- a/tests/unit/test_security.py
+++ b/tests/unit/test_security.py
@@ -603,11 +603,11 @@ async def test_check_usertask(
 
         if is_appropriate == 'No':
             assert len(event_list) == 2
-            assert type(event_list[0]) == MessageAction
-            assert type(event_list[1]) == ChangeAgentStateAction
+            assert isinstance(event_list[0], MessageAction)
+            assert isinstance(event_list[1], ChangeAgentStateAction)
         elif is_appropriate == 'Yes':
             assert len(event_list) == 1
-            assert type(event_list[0]) == MessageAction
+            assert isinstance(event_list[0], MessageAction)
 
 
 @pytest.mark.parametrize(
@@ -665,8 +665,8 @@ async def test_check_fillaction(
 
         if is_harmful == 'Yes':
             assert len(event_list) == 2
-            assert type(event_list[0]) == BrowseInteractiveAction
-            assert type(event_list[1]) == ChangeAgentStateAction
+            assert isinstance(event_list[0], BrowseInteractiveAction)
+            assert isinstance(event_list[1], ChangeAgentStateAction)
         elif is_harmful == 'No':
             assert len(event_list) == 1
-            assert type(event_list[0]) == BrowseInteractiveAction
+            assert isinstance(event_list[0], BrowseInteractiveAction)