Specification of instance weights

[GjjvdBurg]

Currently the package allows for two modes of instance weights: unit weights where each instance gets weight 1 and group weights where instances get weights inversely proportional to the size of their class. In the future, we want to allow the user to specify a vector of weights as well.

If you would like to see this feature added to the Python package sooner, vote on this issue by leaving a 👍 reaction below,