This Python application has a memory leak. Find it and explain the fix. ```python import threading import time from functools import lru_cache class EventProcessor: _instances = [] def __init__(self, name): self.name = name self.callbacks = [] self._lock = threading.Lock() EventProcessor._instances.append(self) def register_callback(self, func): self.callbacks.append(func) @lru_cache(maxsize=10000) def process(self, event_data): results = [] for callback in self.callbacks: result = callback(event_data) results.append(result) return tuple(results) def __del__(self): print(f"Processor {self.name} deleted") def create_processor_for_request(request_id): processor = EventProcessor(f"processor_{request_id}") processor.register_callback(lambda x: x.upper()) processor.register_callback(lambda x: len(x)) return processor # Simulated request handling def handle_request(request_id, data): processor = create_processor_for_request(request_id) return processor.process(data) # This runs for hours... for i in range(1000000): result = handle_request(i, f"event_data_{i}") time.sleep(0.001) ```