diff --git a/scrapy/http/response/__init__.py b/scrapy/http/response/__init__.py
index 79a8d0ca0..b9e638551 100644
--- a/scrapy/http/response/__init__.py
+++ b/scrapy/http/response/__init__.py
@@ -4,6 +4,8 @@ responses in Scrapy.
 
 See documentation in docs/topics/request-response.rst
 """
+from typing import Generator
+
 from six.moves.urllib.parse import urljoin
 
 from scrapy.http.request import Request
@@ -41,8 +43,8 @@ class Response(object_ref):
         if isinstance(url, str):
             self._url = url
         else:
-            raise TypeError('%s url must be str, got %s:' % (type(self).__name__,
-                type(url).__name__))
+            raise TypeError('%s url must be str, got %s:' %
+                            (type(self).__name__, type(url).__name__))
 
     url = property(_get_url, obsolete_setter(_set_url, 'url'))
 
diff --git a/scrapy/http/response/html.py b/scrapy/http/response/html.py
index bd3559fbb..7eed052c2 100644
--- a/scrapy/http/response/html.py
+++ b/scrapy/http/response/html.py
@@ -7,5 +7,6 @@ See documentation in docs/topics/request-response.rst
 
 from scrapy.http.response.text import TextResponse
 
+
 class HtmlResponse(TextResponse):
     pass
diff --git a/scrapy/http/response/text.py b/scrapy/http/response/text.py
index b97420345..6acf1026f 100644
--- a/scrapy/http/response/text.py
+++ b/scrapy/http/response/text.py
@@ -6,6 +6,7 @@ See documentation in docs/topics/request-response.rst
 """
 
 from contextlib import suppress
+from typing import Generator
 
 import parsel
 import six
@@ -14,6 +15,7 @@ from w3lib.encoding import (html_body_declared_encoding, html_to_unicode,
                             http_content_type_encoding, resolve_encoding)
 from w3lib.html import strip_html5_whitespace
 
+from scrapy.http import Request
 from scrapy.http.response import Response
 from scrapy.utils.python import memoizemethod_noargs, to_unicode
 from scrapy.utils.response import get_base_url
diff --git a/scrapy/http/response/xml.py b/scrapy/http/response/xml.py
index 1df33fee5..abf474a2f 100644
--- a/scrapy/http/response/xml.py
+++ b/scrapy/http/response/xml.py
@@ -7,5 +7,6 @@ See documentation in docs/topics/request-response.rst
 
 from scrapy.http.response.text import TextResponse
 
+
 class XmlResponse(TextResponse):
     pass