fix linter warning

Author: mattwang44

Lib/argparse.py

@@ -956,7 +956,7 @@ def __init__(self,
     def __call__(self, parser, namespace, values, option_string=None):
         if '-' not in parser.prefix_chars:
             raise ValueError("BooleanOptionalAction requires '-' in parser's prefix_chars")
-        
+
         if option_string in self.option_strings:
             setattr(namespace, self.dest, not option_string.startswith('--no-'))
 

Lib/test/test_argparse.py

@@ -798,10 +798,10 @@ def test_invalid_name(self):
     def test_prefix_chars_incompatibility(self):
         parser = argparse.ArgumentParser(prefix_chars='+')
         parser.add_argument('++foo', action=argparse.BooleanOptionalAction)
-        
+
         with self.assertRaises(ValueError) as cm:
             parser.parse_args(['++foo'])
-        
+
         self.assertIn(str(cm.exception),
                       "BooleanOptionalAction requires '-' in parser's prefix_chars")