docstr: Returns the number of output variables
docstr_tok: ["Returns","the","number","of","output","variables"]
code: def n_outputs(self):
      """Returns the number of output variables"""
      return self.__n_outputs
  
file_path: OMLT/src/omlt/gbt/model.py
label_desc: Use image node_id 4 for calling the GradientBoostedTreeModel obj's underlying member method code with example usage: obj.n_outputs() and returns: self