When Transform is called without calling Fit, a ValueError is thrown. Something similar to sklearn.exceptions.NotFittedError would be more appropriate?

[skasturi]

Describe the bug
When Transform is called without calling Fit, a ValueError is thrown. Something similar to sklearn.exceptions.NotFittedError would be more appropriate?

To Reproduce
Steps to reproduce the behavior:
Create a nimbusml featurizer and call transform directly without calling fit.

Expected behavior
An error similar to sklearn.exceptions.NotFittedError is what I expected. But it threw a generic ValueError

Screenshots

Desktop (please complete the following information):

• Windows 10