Fix some IDE warnings, mostly around type safety on the Python side

server/handlers/api/dxstats.py

@@ -1,9 +1,12 @@
 import json
 from collections import Counter
 from datetime import datetime, timedelta
+from typing import Any
 
 import pytz
 import tornado
+from tornado import httputil
+from tornado.web import Application
 
 from core.prometheus_metrics_handler import api_requests_counter
 
@@ -16,6 +19,11 @@ BANDS_SET = frozenset(BANDS)
 class APIDxStatsHandler(tornado.web.RequestHandler):
     """API request handler for /api/v1/dxstats"""
 
+    def __init__(self, application: "Application", request: httputil.HTTPServerRequest, **kwargs: Any):
+        self._spots = None
+        self._web_server_metrics = None
+        super().__init__(application, request, **kwargs)
+
     def initialize(self, spots, web_server_metrics):
         self._spots = spots
         self._web_server_metrics = web_server_metrics