EXCEPTION! 'NoneType' object has no attribute 'strip'

# Summary
Fail to run streamlit on Python3.6.3 with anaconda and docker

# Steps to reproduce
Just Type `streamlit hello`

## Expected behavior:
Try to run streamlit according to the document

## Actual behavior:
Make an exception as **EXCEPTION! 'NoneType' object has no attribute 'strip'**
