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: AC.m
    path of file: ./repos/acycle/code/guicode
    
    the code of the file until where you have to start completion: function varargout = AC(varargin)
%% ACYCLE
%% time-series analysis software for paleoclimate projects and education
%%
%
% AC MATLAB code for AC.fig
%
%      This is the main function of the Acycle software.
%
%% ************************************************************************
% Please acknowledge the program author on any publication of scientific 
% results based in part on use of the program and cite the following
% article in which the program was described:
%
%       Mingsong Li, Linda Hinnov, Lee Kump. Acycle: Time-series analysis
%       software for paleoclimate projects and education, Computers & Geosciences,
%       127: 12-22. https://doi.org/10.1016/j.cageo.2019.02.011
%
% If you publish results using techniques such as correlation coefficient,
% sedimentary noise model, power decomposition an
    
function menu_interpolationGUI_Callback(hObject, eventdata, handles)
% hObject    handle to menu_interpolationGUI (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

contents = cellstr(get(handles.listbox_acmain,'String')); % read contents of listbox 1 
plot_selected = get(handles.listbox_acmain,'Value');
nplot = length(plot_selected);   % length
if nplot <= 1
    data_name = char(contents(plot_selected));
    data_name = strrep2(data_name, '<HTML><FONT color="blue">', '</FONT></HTML>');
    GETac_pwd; 
    data_name = fullfile(ac_pwd,data_name);
    if isdir(data_name) == 1
    else
        [~,dat_name,ext] = fileparts(data_name);
        if sum(strcmp(ext,handles.filetype)) > 0
            current_data = load(data_name);
            handles.current_data = current_data;
            handles.data_name = data_name;
            handles.dat_name = dat_name;
            handles.ext = ext;
            guidata(hObject, handles);
            interpolationGUI(handles);
        end