Python nightly (3.7 ?) remove bare strings.

Python compile step seem to remove base string from AST leading to no outputs in ipython:

```
In [1]: "1"

In [2]:
```

Haven't tracked that down yet, I'd like to investigate that before Python 3.7 is out. 

On 3.6 that would give 

```
In [1]: "a"
Out[1]: 'a'

In [2]:
```
