diff --git a/setup.py b/setup.py
index aa309b9..9da4ab3 100644
--- a/setup.py
+++ b/setup.py
@@ -30,7 +30,7 @@ def run_tests(self):
       long_description=open("README.rst").read(),
       classifiers=[
           'Development Status :: 3 - Alpha',
-          'Operating System :: POSIX ',
+          'Operating System :: POSIX',
           'Programming Language :: Python',
           'Programming Language :: Python :: 2.7',
           'Programming Language :: Python :: 3.6',