Dear Sir,

There seems to be a typing mistake in your code snippet, it will be “decisionRegressor = DecisionTreeRegressor()” instead of “decisionRegressor= DecisionTreeRegresson()”. It allows you to customize the behavior of your decision tree model. By using it you can set various customized parameters such as maximum depth of the tree etc.
This snippet of code also can be mentioned as creating an instance of the DecisionTreeRegressor, it’s like creating a blueprint for your decision tree. It can learn patterns from your data and can make predictions, to use this feature first you have to import this class from the scikit-learn library into your code.