Update README.md

README.md

@@ -23,6 +23,6 @@ dataset = "chengxuphd/liar2"
 dataset = datasets.load_dataset(dataset)
 
 statement_train, y_train = dataset["train"]["statement"], dataset["train"]["label"]
-statement_val, y_train = dataset["val"]["statement"], dataset["val"]["label"]
+statement_val, y_train = dataset["validation"]["statement"], dataset["validation"]["label"]
 statement_test, y_test = dataset["test"]["statement"], dataset["test"]["label"]
 ```