[refactor] Adress the francisco's comments

Author: nabenabe0928

autoPyTorch/datasets/base_dataset.py

@@ -188,10 +188,8 @@ def __getitem__(self, index: int, train: bool = True) -> Tuple[np.ndarray, ...]:
             A transformed single point prediction
         """
 
-        if hasattr(self.train_tensors[0], 'loc'):
-            X = self.train_tensors[0].iloc[[index]]
-        else:
-            X = self.train_tensors[0][index]
+        X = self.train_tensors[0].iloc[[index]] if hasattr(self.train_tensors[0], 'loc') \
+            else self.train_tensors[0][index]
 
         if self.train_transform is not None and train:
             X = self.train_transform(X)