Guillaume Lemaitre

The first round of review.

In addition, you need to remove the test that checks for parameter validation of the `SimpleImputer`. I think they are located in `test_impute.py`.

> @glemaitre I couldn't find any parameter validation test in test_impute.py I see the following test to be removed: `test_imputation_error_invalid_strategy`

Pretty nice add-on. Thanks @lucyleeow

I am deeply thinking this is useful if users are reading. But I agree with the assessment of @GaelVaroquaux I would be -1

Of course ;)

> I thought this was outside the scope of the issue/PR. I think it should be done at the same time. Otherwise, we will introduce some duplicated code. We might...

I made a push to resolve the conflicts.

We only need to handle the deprecation in `BaseEnsemble` and will be handled for all estimators that are derived from `BaseEnsemble`. We only need to fix our test to not...

I push a small fix for the documentation. Indeed, one needs to add the docstring to the property. The CIs should be OK now. Let me do a review then.