initDtrees method
Initializes the decision trees
within the forest.
Each of those instantiates a DecisionTreeClassifier.
Implementation
void initDtrees(List<dynamic> trees) {
if (_dtrees.length > 0) return null;
for (int i = 0; i < trees.length; i++) {
trees[i]["classes_"] = classes;
_dtrees.add(DecisionTreeClassifier.fromMap(trees[i]));
}
}