Here are the versions of pyenv that are available on CircleCI (as of time of creation)

pyenv versions available on circle ci

```
ubuntu@box212:~$ pyenv versions
  system
  2.7.10
* 2.7.11 (set by /opt/circleci/.pyenv/version)
  2.7.12
  3.1.4
  3.1.5
  3.2.5
  3.2.6
  3.3.5
  3.3.6
  3.4.3
  3.4.4
  3.5.1
  3.5.2
  3.5.3
  3.6.1
  3.6.2
  pypy-1.9
  pypy-2.6.1
  pypy-4.0.1
```