diff --git a/fuse/utils/ndict.py b/fuse/utils/ndict.py
index a145f711..b849ca14 100644
--- a/fuse/utils/ndict.py
+++ b/fuse/utils/ndict.py
@@ -22,8 +22,8 @@
 
 import copy
 import types
-import numpy
-import torch
+from numpy import ndarray
+from torch import Tensor
 from typing import (
     Any,
     Callable,
@@ -273,7 +273,7 @@ def pop(self, key: str) -> Any:
         del self[key]
         return res
 
-    def indices(self, indices: numpy.ndarray) -> dict:
+    def indices(self, indices: ndarray) -> dict:
         """
         Extract the specified indices from each element in the dictionary (if possible)
 
@@ -286,7 +286,7 @@ def indices(self, indices: numpy.ndarray) -> dict:
         for key in all_keys:
             try:
                 value = self[key]
-                if isinstance(value, (numpy.ndarray, torch.Tensor)):
+                if isinstance(value, (ndarray, Tensor)):
                     new_value = value[indices]
                 elif isinstance(value, Sequence):
                     new_value = [item for i, item in enumerate(value) if indices[i]]