- :class:`tree.ExtraTreeClassifier` and :class:`tree.ExtraTreeRegressor` now
  support missing-values in the data matrix ``X``. Missing-values are handled by
  randomly moving all of the samples to the left, or right child node as the tree is
  traversed.
  By :user:`Adam Li <adam2392>` and :user:`Loïc Estève <lesteve>`
