diff --git a/scrapy/cmdline.py b/scrapy/cmdline.py
index b189e016b..3e88536e4 100644
--- a/scrapy/cmdline.py
+++ b/scrapy/cmdline.py
@@ -19,10 +19,12 @@ def _iter_command_classes(module_name):
     # scrapy.utils.spider.iter_spider_classes
     for module in walk_modules(module_name):
         for obj in vars(module).values():
-            if inspect.isclass(obj) and \
-                    issubclass(obj, ScrapyCommand) and \
-                    obj.__module__ == module.__name__ and \
-                    not obj == ScrapyCommand:
+            if (
+                inspect.isclass(obj)
+                and issubclass(obj, ScrapyCommand)
+                and obj.__module__ == module.__name__
+                and not obj == ScrapyCommand
+            ):
                 yield obj
 
 
diff --git a/scrapy/commands/crawl.py b/scrapy/commands/crawl.py
index e1724c1e6..f205c40b0 100644
--- a/scrapy/commands/crawl.py
+++ b/scrapy/commands/crawl.py
@@ -26,6 +26,8 @@ class Command(BaseRunSpiderCommand):
         else:
             self.crawler_process.start()
 
-            if self.crawler_process.bootstrap_failed or \
-                    (hasattr(self.crawler_process, 'has_exception') and self.crawler_process.has_exception):
+            if (
+                self.crawler_process.bootstrap_failed
+                or hasattr(self.crawler_process, 'has_exception') and self.crawler_process.has_exception
+            ):
                 self.exitcode = 1
diff --git a/scrapy/commands/fetch.py b/scrapy/commands/fetch.py
index 063195f50..95f87e8c3 100644
--- a/scrapy/commands/fetch.py
+++ b/scrapy/commands/fetch.py
@@ -19,8 +19,10 @@ class Command(ScrapyCommand):
         return "Fetch a URL using the Scrapy downloader"
 
     def long_desc(self):
-        return "Fetch a URL using the Scrapy downloader and print its content " \
-            "to stdout. You may want to use --nolog to disable logging"
+        return (
+            "Fetch a URL using the Scrapy downloader and print its content"
+            " to stdout. You may want to use --nolog to disable logging"
+        )
 
     def add_options(self, parser):
         ScrapyCommand.add_options(self, parser)
diff --git a/scrapy/commands/genspider.py b/scrapy/commands/genspider.py
index abf3b7a5c..4c7548e9c 100644
--- a/scrapy/commands/genspider.py
+++ b/scrapy/commands/genspider.py
@@ -121,6 +121,7 @@ class Command(ScrapyCommand):
 
     @property
     def templates_dir(self):
-        _templates_base_dir = self.settings['TEMPLATES_DIR'] or \
-            join(scrapy.__path__[0], 'templates')
-        return join(_templates_base_dir, 'spiders')
+        return join(
+            self.settings['TEMPLATES_DIR'] or join(scrapy.__path__[0], 'templates'),
+            'spiders'
+        )
diff --git a/scrapy/commands/startproject.py b/scrapy/commands/startproject.py
index 852281959..ae4a15b0f 100644
--- a/scrapy/commands/startproject.py
+++ b/scrapy/commands/startproject.py
@@ -137,6 +137,7 @@ class Command(ScrapyCommand):
 
     @property
     def templates_dir(self):
-        _templates_base_dir = self.settings['TEMPLATES_DIR'] or \
-            join(scrapy.__path__[0], 'templates')
-        return join(_templates_base_dir, 'project')
+        return join(
+            self.settings['TEMPLATES_DIR'] or join(scrapy.__path__[0], 'templates'),
+            'project'
+        )
diff --git a/scrapy/commands/view.py b/scrapy/commands/view.py
index 41e77ba3b..908bee966 100644
--- a/scrapy/commands/view.py
+++ b/scrapy/commands/view.py
@@ -8,8 +8,7 @@ class Command(fetch.Command):
         return "Open URL in browser, as seen by Scrapy"
 
     def long_desc(self):
-        return "Fetch a URL using the Scrapy downloader and show its " \
-            "contents in a browser"
+        return "Fetch a URL using the Scrapy downloader and show its contents in a browser"
 
     def add_options(self, parser):
         super(Command, self).add_options(parser)
diff --git a/scrapy/core/engine.py b/scrapy/core/engine.py
index de0da4b70..86a6abb23 100644
--- a/scrapy/core/engine.py
+++ b/scrapy/core/engine.py
@@ -141,10 +141,12 @@ class ExecutionEngine:
 
     def _needs_backout(self, spider):
         slot = self.slot
-        return not self.running \
-            or slot.closing \
-            or self.downloader.needs_backout() \
+        return (
+            not self.running
+            or slot.closing
+            or self.downloader.needs_backout()
             or self.scraper.slot.needs_backout()
+        )
 
     def _next_request_from_scheduler(self, spider):
         slot = self.slot
diff --git a/scrapy/downloadermiddlewares/redirect.py b/scrapy/downloadermiddlewares/redirect.py
index b32afb8e4..366d60dcb 100644
--- a/scrapy/downloadermiddlewares/redirect.py
+++ b/scrapy/downloadermiddlewares/redirect.py
@@ -33,10 +33,8 @@ class BaseRedirectMiddleware:
         if ttl and redirects <= self.max_redirect_times:
             redirected.meta['redirect_times'] = redirects
             redirected.meta['redirect_ttl'] = ttl - 1
-            redirected.meta['redirect_urls'] = request.meta.get('redirect_urls', []) + \
-                [request.url]
-            redirected.meta['redirect_reasons'] = request.meta.get('redirect_reasons', []) + \
-                [reason]
+            redirected.meta['redirect_urls'] = request.meta.get('redirect_urls', []) + [request.url]
+            redirected.meta['redirect_reasons'] = request.meta.get('redirect_reasons', []) + [reason]
             redirected.dont_filter = request.dont_filter
             redirected.priority = request.priority + self.priority_adjust
             logger.debug("Redirecting (%(reason)s) to %(redirected)s from %(request)s",
@@ -99,8 +97,11 @@ class MetaRefreshMiddleware(BaseRedirectMiddleware):
         self._maxdelay = settings.getint('METAREFRESH_MAXDELAY')
 
     def process_response(self, request, response, spider):
-        if request.meta.get('dont_redirect', False) or request.method == 'HEAD' or \
-                not isinstance(response, HtmlResponse):
+        if (
+            request.meta.get('dont_redirect', False)
+            or request.method == 'HEAD'
+            or not isinstance(response, HtmlResponse)
+        ):
             return response
 
         interval, url = get_meta_refresh(response,
diff --git a/scrapy/downloadermiddlewares/retry.py b/scrapy/downloadermiddlewares/retry.py
index 6d11af5b2..67be8c282 100644
--- a/scrapy/downloadermiddlewares/retry.py
+++ b/scrapy/downloadermiddlewares/retry.py
@@ -60,8 +60,10 @@ class RetryMiddleware:
         return response
 
     def process_exception(self, request, exception, spider):
-        if isinstance(exception, self.EXCEPTIONS_TO_RETRY) \
-                and not request.meta.get('dont_retry', False):
+        if (
+            isinstance(exception, self.EXCEPTIONS_TO_RETRY)
+            and not request.meta.get('dont_retry', False)
+        ):
             return self._retry(request, exception, spider)
 
     def _retry(self, request, reason, spider):
diff --git a/scrapy/extensions/memusage.py b/scrapy/extensions/memusage.py
index a0540bf8f..ab2e43e8c 100644
--- a/scrapy/extensions/memusage.py
+++ b/scrapy/extensions/memusage.py
@@ -81,8 +81,10 @@ class MemoryUsage:
             logger.error("Memory usage exceeded %(memusage)dM. Shutting down Scrapy...",
                          {'memusage': mem}, extra={'crawler': self.crawler})
             if self.notify_mails:
-                subj = "%s terminated: memory usage exceeded %dM at %s" % \
-                        (self.crawler.settings['BOT_NAME'], mem, socket.gethostname())
+                subj = (
+                    "%s terminated: memory usage exceeded %dM at %s"
+                    % (self.crawler.settings['BOT_NAME'], mem, socket.gethostname())
+                )
                 self._send_report(self.notify_mails, subj)
                 self.crawler.stats.set_value('memusage/limit_notified', 1)
 
@@ -102,8 +104,10 @@ class MemoryUsage:
             logger.warning("Memory usage reached %(memusage)dM",
                            {'memusage': mem}, extra={'crawler': self.crawler})
             if self.notify_mails:
-                subj = "%s warning: memory usage reached %dM at %s" % \
-                        (self.crawler.settings['BOT_NAME'], mem, socket.gethostname())
+                subj = (
+                    "%s warning: memory usage reached %dM at %s"
+                    % (self.crawler.settings['BOT_NAME'], mem, socket.gethostname())
+                )
                 self._send_report(self.notify_mails, subj)
                 self.crawler.stats.set_value('memusage/warning_notified', 1)
             self.warned = True
diff --git a/scrapy/http/request/form.py b/scrapy/http/request/form.py
index cd4e3373f..0e6ceef0b 100644
--- a/scrapy/http/request/form.py
+++ b/scrapy/http/request/form.py
@@ -205,8 +205,7 @@ def _get_clickable(clickdata, form):
 
     # We didn't find it, so now we build an XPath expression out of the other
     # arguments, because they can be used as such
-    xpath = u'.//*' + \
-            u''.join(u'[@%s="%s"]' % c for c in clickdata.items())
+    xpath = u'.//*' + u''.join(u'[@%s="%s"]' % c for c in clickdata.items())
     el = form.xpath(xpath)
     if len(el) == 1:
         return (el[0].get('name'), el[0].get('value') or '')
diff --git a/scrapy/http/response/text.py b/scrapy/http/response/text.py
index b43fe5c19..0f300c8da 100644
--- a/scrapy/http/response/text.py
+++ b/scrapy/http/response/text.py
@@ -62,8 +62,11 @@ class TextResponse(Response):
         return self._declared_encoding() or self._body_inferred_encoding()
 
     def _declared_encoding(self):
-        return self._encoding or self._headers_encoding() \
+        return (
+            self._encoding
+            or self._headers_encoding()
             or self._body_declared_encoding()
+        )
 
     def body_as_unicode(self):
         """Return body as unicode"""
diff --git a/scrapy/link.py b/scrapy/link.py
index 7cb0765cc..1ef50b113 100644
--- a/scrapy/link.py
+++ b/scrapy/link.py
@@ -21,12 +21,18 @@ class Link:
         self.nofollow = nofollow
 
     def __eq__(self, other):
-        return self.url == other.url and self.text == other.text and \
-            self.fragment == other.fragment and self.nofollow == other.nofollow
+        return (
+            self.url == other.url
+            and self.text == other.text
+            and self.fragment == other.fragment
+            and self.nofollow == other.nofollow
+        )
 
     def __hash__(self):
         return hash(self.url) ^ hash(self.text) ^ hash(self.fragment) ^ hash(self.nofollow)
 
     def __repr__(self):
-        return 'Link(url=%r, text=%r, fragment=%r, nofollow=%r)' % \
-            (self.url, self.text, self.fragment, self.nofollow)
+        return (
+            'Link(url=%r, text=%r, fragment=%r, nofollow=%r)'
+            % (self.url, self.text, self.fragment, self.nofollow)
+        )
diff --git a/scrapy/settings/__init__.py b/scrapy/settings/__init__.py
index b9a13c018..ff8317cd1 100644
--- a/scrapy/settings/__init__.py
+++ b/scrapy/settings/__init__.py
@@ -52,8 +52,7 @@ class SettingsAttribute:
             self.priority = priority
 
     def __str__(self):
-        return "<SettingsAttribute value={self.value!r} " \
-               "priority={self.priority}>".format(self=self)
+        return "<SettingsAttribute value={self.value!r} priority={self.priority}>".format(self=self)
 
     __repr__ = __str__
 
diff --git a/scrapy/utils/benchserver.py b/scrapy/utils/benchserver.py
index 9d8d64612..f595a1acb 100644
--- a/scrapy/utils/benchserver.py
+++ b/scrapy/utils/benchserver.py
@@ -28,8 +28,7 @@ class Root(Resource):
 
 
 def _getarg(request, name, default=None, type=str):
-    return type(request.args[name][0]) \
-        if name in request.args else default
+    return type(request.args[name][0]) if name in request.args else default
 
 
 if __name__ == '__main__':
diff --git a/scrapy/utils/conf.py b/scrapy/utils/conf.py
index 5921f82bf..728bb5f1b 100644
--- a/scrapy/utils/conf.py
+++ b/scrapy/utils/conf.py
@@ -101,11 +101,13 @@ def get_config(use_closest=True):
 
 
 def get_sources(use_closest=True):
-    xdg_config_home = os.environ.get('XDG_CONFIG_HOME') or \
-        os.path.expanduser('~/.config')
-    sources = ['/etc/scrapy.cfg', r'c:\scrapy\scrapy.cfg',
-               xdg_config_home + '/scrapy.cfg',
-               os.path.expanduser('~/.scrapy.cfg')]
+    xdg_config_home = os.environ.get('XDG_CONFIG_HOME') or os.path.expanduser('~/.config')
+    sources = [
+        '/etc/scrapy.cfg',
+        r'c:\scrapy\scrapy.cfg',
+        xdg_config_home + '/scrapy.cfg',
+        os.path.expanduser('~/.scrapy.cfg'),
+    ]
     if use_closest:
         sources.append(closest_scrapy_cfg())
     return sources
diff --git a/scrapy/utils/curl.py b/scrapy/utils/curl.py
index 67b22dbc5..aa681522f 100644
--- a/scrapy/utils/curl.py
+++ b/scrapy/utils/curl.py
@@ -9,8 +9,7 @@ from w3lib.http import basic_auth_header
 
 class CurlParser(argparse.ArgumentParser):
     def error(self, message):
-        error_msg = \
-            'There was an error parsing the curl command: {}'.format(message)
+        error_msg = 'There was an error parsing the curl command: {}'.format(message)
         raise ValueError(error_msg)
 
 
diff --git a/scrapy/utils/ossignal.py b/scrapy/utils/ossignal.py
index 45c9cef0c..cf867f3f8 100644
--- a/scrapy/utils/ossignal.py
+++ b/scrapy/utils/ossignal.py
@@ -18,8 +18,7 @@ def install_shutdown_handlers(function, override_sigint=True):
     from twisted.internet import reactor
     reactor._handleSignals()
     signal.signal(signal.SIGTERM, function)
-    if signal.getsignal(signal.SIGINT) == signal.default_int_handler or \
-            override_sigint:
+    if signal.getsignal(signal.SIGINT) == signal.default_int_handler or override_sigint:
         signal.signal(signal.SIGINT, function)
     # Catch Ctrl-Break in windows
     if hasattr(signal, 'SIGBREAK'):
diff --git a/scrapy/utils/response.py b/scrapy/utils/response.py
index edbc0db25..c29b619ce 100644
--- a/scrapy/utils/response.py
+++ b/scrapy/utils/response.py
@@ -47,13 +47,17 @@ def response_httprepr(response):
     is provided only for reference, since it's not the exact stream of bytes
     that was received (that's not exposed by Twisted).
     """
-    s = b"HTTP/1.1 " + to_bytes(str(response.status)) + b" " + \
-        to_bytes(http.RESPONSES.get(response.status, b'')) + b"\r\n"
+    values = [
+        b"HTTP/1.1 ",
+        to_bytes(str(response.status)),
+        b" ",
+        to_bytes(http.RESPONSES.get(response.status, b'')),
+        b"\r\n",
+    ]
     if response.headers:
-        s += response.headers.to_string() + b"\r\n"
-    s += b"\r\n"
-    s += response.body
-    return s
+        values.extend([response.headers.to_string(), b"\r\n"])
+    values.extend([b"\r\n", response.body])
+    return b"".join(values)
 
 
 def open_in_browser(response, _openfunc=webbrowser.open):
diff --git a/scrapy/utils/spider.py b/scrapy/utils/spider.py
index 7e7a50c88..f3a9a67a3 100644
--- a/scrapy/utils/spider.py
+++ b/scrapy/utils/spider.py
@@ -34,10 +34,12 @@ def iter_spider_classes(module):
     from scrapy.spiders import Spider
 
     for obj in vars(module).values():
-        if inspect.isclass(obj) and \
-           issubclass(obj, Spider) and \
-           obj.__module__ == module.__name__ and \
-           getattr(obj, 'name', None):
+        if (
+            inspect.isclass(obj)
+            and issubclass(obj, Spider)
+            and obj.__module__ == module.__name__
+            and getattr(obj, 'name', None)
+        ):
             yield obj