1 Imputation
2my_imputer = SimpleImputer()
3imputed_X_train = pd.DataFrame(my_imputer.fit_transform(X_train))
4imputed_X_valid = pd.DataFrame(my_imputer.transform(X_valid))
5
6# Imputation removed column names; put them back
7imputed_X_train.columns = X_train.columns
8imputed_X_valid.columns = X_valid.columns