DummyClassifier makes predictions that ignore the input features.
This classifier serves as a simple baseline to compare against other more
complex classifiers.
The specific behavior of the baseline is selected with the `strategy`
parameter.
All strategies make predictions that ignore the input feature values passed
as the `X` argument to `fit` and `predict`. The predictions, however,
typically depend on values observed in the `y` parameter passed to `fit`.
Note that the "stratified" and "uniform" strategies lead to
non-deterministic predictions that can be rendered deterministic by setting
the `random_state` parameter if needed. The other strategies are naturally
deterministic and, once fit, always return the same constant prediction
for any value of `X`.