If you have questions about a specific use case, or you are not sure whether this is a bug or not, please post it to our discourse channel: https://discourse.pymc.io  

## Description of your problem

**Please provide a minimal, self-contained, and reproducible example.**
```python
[Your code here]
```

**Please provide the full traceback.**
```python
[The error output here]
```

**Please provide any additional information below.**


## Versions and main components

* PyMC3 Version:
* Theano Version:
* Python Version:
* Operating system:
* How did you install PyMC3: (conda/pip)