Ridge' is not a CV regularization model; try ManualAlphaSelection instead

[mmhernandm]

Describe the bug
I am trying to find the best Alpha for a Ridge model without CV using Yellowbrick ManualAlphaSelection API. My code is pretty basic and it has been taken from the yellowbrick´s documentation. Even though it does not work:

To Reproduce

from yellowbrick.regressor import ManualAlphaSelection
from sklearn.linear_model import Ridge
model = ManualAlphaSelection(Ridge(), scoring='neg_mean_squared_error')
model.fit(X_train, y_train)
model.show()
`
Dataset
The dataset does not matter because the code itself does not Works. It is a syntax problem.

Expected behavior
It was expected that ManualAlphaSelection Works but Python raises the message: 'Ridge' is not a CV regularization model; try ManualAlphaSelection instead. But this message is wrong because the ManualAlphaSelection is already being used

Traceback

If applicable, add the traceback from the exception.

Desktop (please complete the following information):

• OS: Windows 10
• Python Version Anaconda3 Python 3
• Yellowbrick Version is the last on because I just installed it on march the 19th. I don´t know how to check this out.

Additional context Jupyter notebook 6.0.3

[bbengfort]

@mmhernandm this is a known bug, but it's slipped past us for a while since we didn't have an issue for it. Thanks for opening it - we will apply a patch before our next release.

[bbengfort]

@rebeccabilbro it would be nice to know what it would take to make ManualAlphaSelection green and create an issue for it.

Also, is #157 related? If not, could we add it to the above issue.