Build fails with python3.3 and under

Hi, I’m using travis to build and test my project. Here is the link. Build and test for python>=3.4 works perfectly but it fails for all python <=3.3 with this error log:

Downloading archive: https://storage.googleapis.com/travis-ci-language-archives/python/binaries/ubuntu/16.04/x86_64/python-3.3.tar.bz2

1640.10s$ curl -sSf --retry 5 -o python-3.3.tar.bz2 ${archive_url}

165curl: (22) The requested URL returned error: 404 Not Found

166Unable to download 3.3 archive. The archive may not exist. Please consider a different version.

Can someone help me please?