Fix bug in --help from percent sign in help string

train.py

@@ -384,7 +384,7 @@ if __name__ == '__main__':
     parser.add_argument('--weights', type=str, default='', help='initial weights path')
     parser.add_argument('--name', default='', help='renames results.txt to results_name.txt if supplied')
     parser.add_argument('--device', default='', help='cuda device, i.e. 0 or 0,1,2,3 or cpu')
-    parser.add_argument('--multi-scale', action='store_true', help='vary img-size +/- 50%')
+    parser.add_argument('--multi-scale', action='store_true', help='vary img-size +/- 50%%')
     parser.add_argument('--single-cls', action='store_true', help='train as single-class dataset')
     parser.add_argument('--hyp', type=str, default='', help ='hyp cfg path [*.yaml].')
     opt = parser.parse_args()