Fix typos

run.py

@@ -60,7 +60,7 @@ if __name__ == '__main__':
                         required=True)
     parser.add_argument('--length_constraint', type=str, choices=['sentences', 'tokens'], default='sentences',
                         help='what constraint to impose on the length of the generated timeline '
-                             '(number of setences or number of tokens',
+                             '(number of sentences or number of tokens)',
                         required=True)
     parser.add_argument('--print_timelines',
                         action='store_true',