To make py35 running in your development env, you should:

• Install pyenv in your workstation, please follow the guide to install/update:

https://github.com/pyenv/pyenv-installer

• Use pyenv to install python35

$ pyenv install 3.5.4

• Set pyenv in SDK dir

$ cd <sdk_dir>
$ pyenv local 2.7.5 3.5.4

• Run tox

$ tox -v -epy35

• other:

if use py3 after python-xxx-sdk installed, you need:
$ cd <sdk_dir>
$ pyenv local 3.5.4 2.7.5
$ python ./setup.py install