diff --git a/scrapy/core/downloader/handlers/http2.py b/scrapy/core/downloader/handlers/http2.py
index f2ed40f9b..ddd813cec 100644
--- a/scrapy/core/downloader/handlers/http2.py
+++ b/scrapy/core/downloader/handlers/http2.py
@@ -29,7 +29,7 @@ class H2DownloadHandler:
     def from_crawler(cls, crawler):
         return cls(crawler.settings, crawler)
 
-    def download_request(self, request: Request, spider: Spider):
+    def download_request(self, request: Request, spider: Spider) -> Deferred:
         agent = ScrapyH2Agent(
             context_factory=self._context_factory,
             pool=self._pool,
diff --git a/scrapy/core/http2/stream.py b/scrapy/core/http2/stream.py
index bddf50a56..33302421e 100644
--- a/scrapy/core/http2/stream.py
+++ b/scrapy/core/http2/stream.py
@@ -5,7 +5,7 @@ from typing import List, Optional, Tuple, TYPE_CHECKING
 from urllib.parse import urlparse
 
 from h2.errors import ErrorCodes
-from h2.exceptions import H2Error, StreamClosedError, ProtocolError
+from h2.exceptions import H2Error, ProtocolError, StreamClosedError
 from hpack import HeaderTuple
 from twisted.internet.defer import Deferred, CancelledError
 from twisted.internet.error import ConnectionClosed