Update README.md

Author: rab657

README.md

@@ -45,7 +45,8 @@ from explainx import *
 Load dataset as a dataframe & pass X_Data, Y_Data in your XGBoost Model
 
 ```python
-X_data, Y_data = explainx.dataset_boston()
+#X_Data = Pandas DataFrame, Y_Data = Pandas Series
+X_Data, Y_Data = explainx.dataset_boston()
 
 model = xgboost.train({"learning_rate": 0.01}, xgboost.DMatrix(X, label=Y_data), 100)
 ```