Hello, I hope everything is fine. After evaluating the issue you submitted, I was able to find a series of issues that may have implicated in this case. However, in general, the problem is correlated with the following issues:

API problem

• The API currently used by this version of the project can no longer be accessed in the same way as before. This problem has been solved in the following FORK of the project fork.

Only model class

• Furthermore, the StockStat class is only a model class. Because of this, if you are trying to directly access its data, it will not be possible to load the API data, as it does not handle this communication on its own.

Another Yahoo Finance problem

• Finally, as indicated in the class itself, any other issue that prevents direct communication with Yahoo Finance will result in the return of null values.
  

from yahoofinance-api.