diff --git a/README.md b/README.md
index 96604f5..5a012c6 100644
--- a/README.md
+++ b/README.md
@@ -2,7 +2,7 @@
 
 A small tool for PyTorch training.
 
-Check [doc string of `Trainer` class](https://github.com/idorce/torchtrain/blob/master/torchtrain/trainer.py) for usage.
+Check [doc string of `Trainer` class](https://github.com/idorce/torchtrain/blob/c0b32e91bc76fd638f035be11f64e5ac412596a1/torchtrain/trainer.py#L13-L36) for usage.
 
 ```
 pip install torchtrain