chore: apply ruff linting fixes to events module

fix: apply ruff linting to events

src/crewai/events/event_bus.py

@@ -1,8 +1,9 @@
 from __future__ import annotations
 
 import threading
+from collections.abc import Callable
 from contextlib import contextmanager
-from typing import Any, Callable, Dict, List, Type, TypeVar, cast
+from typing import Any, TypeVar, cast
 
 from blinker import Signal
 
@@ -25,17 +26,17 @@ class CrewAIEventsBus:
         if cls._instance is None:
             with cls._lock:
                 if cls._instance is None:  # prevent race condition
-                    cls._instance = super(CrewAIEventsBus, cls).__new__(cls)
+                    cls._instance = super().__new__(cls)
                     cls._instance._initialize()
         return cls._instance
 
     def _initialize(self) -> None:
         """Initialize the event bus internal state"""
         self._signal = Signal("crewai_event_bus")
-        self._handlers: Dict[Type[BaseEvent], List[Callable]] = {}
+        self._handlers: dict[type[BaseEvent], list[Callable]] = {}
 
     def on(
-        self, event_type: Type[EventT]
+        self, event_type: type[EventT]
     ) -> Callable[[Callable[[Any, EventT], None]], Callable[[Any, EventT], None]]:
         """
         Decorator to register an event handler for a specific event type.
@@ -61,6 +62,18 @@ class CrewAIEventsBus:
 
         return decorator
 
+    @staticmethod
+    def _call_handler(
+        handler: Callable, source: Any, event: BaseEvent, event_type: type
+    ) -> None:
+        """Call a single handler with error handling."""
+        try:
+            handler(source, event)
+        except Exception as e:
+            print(
+                f"[EventBus Error] Handler '{handler.__name__}' failed for event '{event_type.__name__}': {e}"
+            )
+
     def emit(self, source: Any, event: BaseEvent) -> None:
         """
         Emit an event to all registered handlers
@@ -72,17 +85,12 @@ class CrewAIEventsBus:
         for event_type, handlers in self._handlers.items():
             if isinstance(event, event_type):
                 for handler in handlers:
-                    try:
-                        handler(source, event)
-                    except Exception as e:
-                        print(
-                            f"[EventBus Error] Handler '{handler.__name__}' failed for event '{event_type.__name__}': {e}"
-                        )
+                    self._call_handler(handler, source, event, event_type)
 
         self._signal.send(source, event=event)
 
     def register_handler(
-        self, event_type: Type[EventTypes], handler: Callable[[Any, EventTypes], None]
+        self, event_type: type[EventTypes], handler: Callable[[Any, EventTypes], None]
     ) -> None:
         """Register an event handler for a specific event type"""
         if event_type not in self._handlers: