You're looking at StableBuild's Deleted PyPI mirror - where we index all deleted packages from the Python package registry.
aliyun-oss2 was reported malicious
OSV:MAL-2023-8356 - Malicious code in aliyun-oss2 (PyPI)

aliyun-oss2
2.18.1

This version was deleted from PyPI around 2023-09-27. Installing fails with:
$ pip3 install aliyun-oss2==2.18.1 ERROR: Could not find a version that satisfies the requirement aliyun-oss2==2.18.1
View other deleted versions of aliyun-oss2

Install through StableBuild

You can install this package from StableBuild's PyPI snapshots from before the version was deleted:
pip3 install \ -i https://YOUR_API_KEY.pypimirror.stablebuild.com/2023-09-26/ \ aliyun-oss2==2.18.1
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Or, download files manually

And install manually via pip:
aliyun-oss2-2.18.1.tar.gz (234.9KB)