Causal Graph not provided. DoWhy will construct a graph based on data inputs.

[harimshin]

Describe the bug
I get messages "Causal Graph not provided. DoWhy will construct a graph based on data inputs." when trying to create causal graph.

Steps to reproduce the behavior
Please see In [8] of following link:
https://github.com/harimshin/bug_report/blob/d8fad99ead7cd27e09bec7a3343f105775e00130/DoWhy_Causal_Graph_error.ipynb
You can read message as "WARNING:dowhy.causal_model:Causal Graph not provided. DoWhy will construct a graph based on data inputs."

Expected behavior
I expected to see a graph in In [10] of following link:
https://github.com/py-why/EconML/blob/7793184ed3fd336ecb92866a7c90f0e266acbed4/notebooks/CustomerScenarios/Case%20Study%20-%20Recommendation%20AB%20Testing%20at%20An%20Online%20Travel%20Company%20-%20EconML%20%2B%20DoWhy.ipynb

Version information:

• 0.11

[drawlinson]

This message is normal when you don't provide an explicit graph. Instead, DoWhy tries to construct a graph based on your arguments specifying treatment, outcome and confounding variables.