diff --git a/maint/requirements.txt b/maint/requirements.txt
index eccf2d9a683cf3ec775a2d2c3fe7cffd5f209a35..eaa02ea57ba3191bf905b42c0f3db3129f4c5749 100644
--- a/maint/requirements.txt
+++ b/maint/requirements.txt
@@ -1,40 +1,44 @@
 alabaster==0.7.10
-appdirs==1.4.3
-args==0.1.0
-attrs==16.3.0
-Automat==0.5.0
-autopep8==1.3.1
-Babel==2.4.0
-clint==0.5.1
+attrs==17.4.0
+Automat==0.6.0
+autopep8==1.3.4
+Babel==2.5.3
+certifi==2018.1.18
+chardet==3.0.4
 constantly==15.1.0
-coverage==4.3.4
-docutils==0.13.1
-flake8==3.3.0
-imagesize==0.7.1
-incremental==16.10.1
-Jinja2==2.9.6
+coverage==4.5.1
+docutils==0.14
+flake8==3.5.0
+hyperlink==18.0.0
+idna==2.6
+imagesize==1.0.0
+incremental==17.5.0
+Jinja2==2.10
 MarkupSafe==1.0
 mccabe==0.6.1
-packaging==16.8
-pep8==1.7.0
-pkginfo==1.4.1
-pluggy==0.4.0
-py==1.4.33
-pycares==2.1.1
+packaging==17.1
+pep8==1.7.1
+pkginfo==1.4.2
+pluggy==0.6.0
+py==1.5.2
+pycares==2.3.0
 pycodestyle==2.3.1
-pycurl==7.43.0
-pyflakes==1.5.0
+pycurl==7.43.0.1
+pyflakes==1.6.0
 Pygments==2.2.0
 pyparsing==2.2.0
-pytz==2017.2
-requests==2.13.0
-requests-toolbelt==0.7.1
-six==1.10.0
+pytz==2018.3
+requests==2.18.4
+requests-toolbelt==0.8.0
+six==1.11.0
 snowballstemmer==1.2.1
-Sphinx==1.5.5
+Sphinx==1.7.1
 sphinx-rtd-theme==0.2.4
-tox==2.7.0
-twine==1.8.1
-Twisted==17.1.0
+sphinxcontrib-websupport==1.0.1
+tox==2.9.1
+tqdm==4.19.8
+twine==1.10.0
+Twisted==17.9.0
+urllib3==1.22
 virtualenv==15.1.0
-zope.interface==4.3.3
+zope.interface==4.4.3
diff --git a/setup.py b/setup.py
index 2bfa07578c1840a66e4d382f1945dee480159b66..be3e3d1b0820df1a690f978daf50d47f30c0560a 100644
--- a/setup.py
+++ b/setup.py
@@ -68,10 +68,10 @@ Fedora users should issue the following command:
 
     $ sudo dnf install gcc python-devel
 
-If you are seeing this message on OSX please read the documentation
-here:
+MacOS users should run:
+
+    $ xcode-select --install
 
-http://api.mongodb.org/python/current/installation.html#osx
 ********************************************************************
 """
 
diff --git a/tornado/gen.py b/tornado/gen.py
index 0ef7c9fc50eff331ec6b5c0c953f83e3a75b7c09..ef70374a70dbd69db163dc992b606d925a46c72f 100644
--- a/tornado/gen.py
+++ b/tornado/gen.py
@@ -1195,7 +1195,7 @@ class Runner(object):
         elif not self.future.done():
             def inner(f):
                 # Break a reference cycle to speed GC.
-                f = None # noqa
+                f = None  # noqa
                 self.run()
             self.io_loop.add_future(
                 self.future, inner)
diff --git a/tornado/test/httpclient_test.py b/tornado/test/httpclient_test.py
index e184625ec5c321e27b0d54836a92beb76264fe03..a76d9eaee92c0c6d2a8b48d9b0f2f8bf52abf984 100644
--- a/tornado/test/httpclient_test.py
+++ b/tornado/test/httpclient_test.py
@@ -608,6 +608,7 @@ class SyncHTTPClientTest(unittest.TestCase):
             # the client finishes with the response (this is noticeable
             # with http/2, which leaves a Future with an unexamined
             # StreamClosedError on the loop).
+
             @gen.coroutine
             def slow_stop():
                 # The number of iterations is difficult to predict. Typically,
diff --git a/tornado/test/import_test.py b/tornado/test/import_test.py
index d8cf14a557ba99677cae3c92ebf5d0f2df658204..0e981482ef92dab1b464f217ab9861f854a7ff72 100644
--- a/tornado/test/import_test.py
+++ b/tornado/test/import_test.py
@@ -48,6 +48,8 @@ class ImportTest(unittest.TestCase):
 
     def test_import_aliases(self):
         # Ensure we don't delete formerly-documented aliases accidentally.
-        import tornado.ioloop, tornado.gen, tornado.util
+        import tornado.ioloop
+        import tornado.gen
+        import tornado.util
         self.assertIs(tornado.ioloop.TimeoutError, tornado.util.TimeoutError)
         self.assertIs(tornado.gen.TimeoutError, tornado.util.TimeoutError)
diff --git a/tornado/test/websocket_test.py b/tornado/test/websocket_test.py
index 2e14342c197939572d8ad4b5aeffe6b753bab5a3..4fb918ec946f0bd64edf6f6d9e3b787fb5bf26f9 100644
--- a/tornado/test/websocket_test.py
+++ b/tornado/test/websocket_test.py
@@ -25,7 +25,9 @@ except ImportError:
     traceback.print_exc()
     raise
 
-from tornado.websocket import WebSocketHandler, websocket_connect, WebSocketError, WebSocketClosedError
+from tornado.websocket import (
+    WebSocketHandler, websocket_connect, WebSocketError, WebSocketClosedError,
+)
 
 try:
     from tornado import speedups