[pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

Author: pre-commit-ci[bot]

tests/test_meta_tensor.py

@@ -17,7 +17,6 @@
 import string
 import tempfile
 import unittest
-import warnings
 from copy import deepcopy
 from multiprocessing.reduction import ForkingPickler