ImportError: No module named 'sklearn.lda'
In case you are using new version and using 
from sklearn.qda import QDA
it will give error, try
from sklearn.discriminant_analysis import QuadraticDiscriminantAnalysis
When I run classifier.py in the openface demos directory using: 
classifier.py train ./generated-embeddings/
I get the following error message:

--> from sklearn.lda import LDA
ModuleNotFoundError: No module named 'sklearn.lda'.

I think to have correctly installed sklearn.
What could be the reason for this message?