[py] missing parentheses for method call

Author: lmtierney

py/test/unit/selenium/webdriver/chrome/chrome_options_tests.py

@@ -114,15 +114,15 @@ def test_get_experimental_options(options):
 def test_set_headless(options):
     options.headless = True
     assert '--headless' in options._arguments
-    if platform.system().lower == 'windows':
+    if platform.system().lower() == 'windows':
         assert '--disable-gpu' in options._arguments
 
 
 def test_unset_headless(options):
     options._arguments = ['--headless', '--disable-gpu']
     options.headless = False
     assert '--headless' not in options._arguments
-    if platform.system().lower == 'windows':
+    if platform.system().lower() == 'windows':
         assert '--disable-gpu' not in options._arguments