Warn: Cannot read property 'toCommandArgument' of undefined

[ryzejiang]

Environment data

VS Code version: 1.19.3
Python Extension version: 2018.1.0
Python Version: 3.6.4
OS and version: macOS High Sierra 10.13.3

Actual behavior

Warn: Cannot read property 'toCommandArgument' of undefined

For some time now I have had a key binding within VS Code that runs the python script I am working on in the terminal.
This has so far been working without issues, until today when I start getting the following error:
Warn: Cannot read property 'toCommandArgument' of undefined

And it is my pythonPath:
"python.pythonPath": "/Users/ryze/anaconda3/envs/tensorflow/bin"

Expected behavior

Steps to reproduce:

Logs

Output from Python output panel

Output from Console window (Help->Developer Tools menu)

[brettcannon]

Duplicate of #689