Investigate warnings

[abigailgold]

tests/test_minimizer.py: 16473 tests with warnings
/site-packages/sklearn/base.py:450: UserWarning: X does not have valid feature names, but DecisionTreeClassifier was fitted with feature names

tests/test_minimizer.py: 1068 tests with warnings
/site-packages/sklearn/base.py:450: UserWarning: X does not have valid feature names, but DecisionTreeRegressor was fitted with feature names

tests/test_minimizer.py::test_keras_model
tests/test_model.py::test_keras_classifier
tests/test_model.py::test_keras_regressor
/site-packages/keras/engine/training_v1.py:2079: UserWarning: Model.state_updates will be removed in a future version. This property should not be used in TensorFlow 2.0, as updates are applied automatically.
updates=self.state_updates,