You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: AnnManager.m
    path of file: ./repos/AI-mag/src/ann_regression/ann_matlab/@AnnManager
    
    the code of the file until where you have to start completion: classdef AnnManager < handle
    % Interface for regression/fitting, meant for ANN.
    %
    %    Offer many functionalities for ANN regression:
    %        - Scaling, variable transformation and normalization
    %        - Checking bounds on the datasets
    %        - Training/fitting the data
    %        - Displaying and plotting error metrics
    %    
    
function self = AnnManager(ann_input)
            % Constructor.
            %
            %    Set the data.
            %    Start and init the regression engine.
            %    Do not make any fitting.
            %
            %    Parameters:
            %        ann_input (struct): input data (variables definition and algoritm parameters)
            
            % assign input
            self.var_inp = ann_input.var_inp;
            self.var_out = ann_input.var_out;
            self.split_train_test = ann_input.split_train_test;
            self.split_var = ann_input.split_var;
            self.ann_info = ann_input.ann_info;
            
            % the training/fitting is not yet done
            self.is_train = false;
            
            % init the regression engine
            self.init_engine();
        end