Fix version check bug (#940)

Summary:
By default: `"1.8.0" > "1.10.0"` will be equal to True, despite 1.10 being a later version that 1.8.0. This PR fixes this issue.

Pull Request resolved: #940

Reviewed By: NarineK

Differential Revision: D36336547

Pulled By: vivekmig

fbshipit-source-id: 84f277eb1e6897a8378ce9eb8c9eab3285ad8494

Author: ProGamerGov

tests/utils/test_sample_gradient.py

@@ -5,6 +5,7 @@
 
 import torch
 from captum._utils.sample_gradient import SampleGradientWrapper, SUPPORTED_MODULES
+from packaging import version
 from tests.helpers.basic import assertTensorAlmostEqual, BaseTest
 from tests.helpers.basic_models import (
     BasicModel_ConvNet_One_Conv,
@@ -37,7 +38,7 @@ def test_sample_grads_conv_mean_multi_inp(self) -> None:
         self._compare_sample_grads_per_sample(model, inp, lambda x: torch.mean(x))
 
     def test_sample_grads_modified_conv_mean(self) -> None:
-        if torch.__version__ < "1.8":
+        if version.parse(torch.__version__) < version.parse("1.8.0"):
             raise unittest.SkipTest(
                 "Skipping sample gradient test with 3D linear module"
                 "since torch version < 1.8"
@@ -50,7 +51,7 @@ def test_sample_grads_modified_conv_mean(self) -> None:
         )
 
     def test_sample_grads_modified_conv_sum(self) -> None:
-        if torch.__version__ < "1.8":
+        if version.parse(torch.__version__) < version.parse("1.8.0"):
             raise unittest.SkipTest(
                 "Skipping sample gradient test with 3D linear module"
                 "since torch version < 1.8"