calculate_variable_split
                        Internal Function for Split Points for Selected
                        Variables
calculate_weight        Calculated empirical density and weight based
                        on variable split.
global_variable_importance
                        Global Variable Importance measure based on
                        Partial Dependence profiles.
local_variable_importance
                        Local Variable Importance measure based on
                        Ceteris Paribus profiles.
plot.global_importance
                        Plot Global Variable Importance measure
plot.local_importance   Plot Local Variable Importance measure
