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: process_pac.m
    path of file: ./repos/brainstorm3/toolbox/process/functions
    
    the code of the file until where you have to start completion: function varargout = process_pac( varargin )
% PROCESS_PAC: Compute the Phase-Amplitude Coupling in one of several time series (directPAC)
%
% DOCUMENTATION:  For more information, please refer to the method described in the following article
%    Özkurt TE, Schnitzler A, J Neurosci Methods. 2011 Oct 15;201(2):438-43
%    "A critical note on the definition of phase-amplitude cross-frequency coupling"

% @=============================================================================
% This function is part of the Brainstorm software:
% https://neuroimage.usc.edu/brainstorm
% 
    
function sProcess = GetDescription() %#ok<DEFNU>
    % Description the process
    sProcess.Comment     = 'Phase-amplitude coupling';
    sProcess.Category    = 'Custom';
    sProcess.SubGroup    = 'Frequency';
    sProcess.Index       = 660;
    sProcess.Description = 'https://neuroimage.usc.edu/brainstorm/Tutorials/TutPac#PAC_estimation';
    % Definition of the input accepted by this process
    sProcess.InputTypes  = {'raw',      'data',     'results',  'matrix'};
    sProcess.OutputTypes = {'timefreq', 'timefreq', 'timefreq', 'timefreq'};
    sProcess.nInputs     = 1;
    sProcess.nMinFiles   = 1;

    % ==== INPUT ====
    sProcess.options.label_in.Comment = '<B><U>Input options</U></B>:';
    sProcess.options.label_in.Type    = 'label';
    % === TIME WINDOW
    sProcess.options.timewindow.Comment = 'Time window:';
    sProcess.options.timewindow.Type    = 'timewindow';
    sProcess.options.timewindow.Value   = [];
    % === SENSOR SELECTION
    sProcess.options.target_data.Comment    = 'Sensor types or names (empty=all): ';
    sProcess.options.target_data.Type       = 'text';
    sProcess.options.target_data.Value      = 'MEG, EEG';
    sProcess.options.target_data.InputTypes = {'data', 'raw'};
    % === SCOUTS SELECTION
    sProcess.options.scouts.Comment    = 'Use scouts';
    sProcess.options.scouts.Type       = 'scout_confirm';
    sProcess.options.scouts.Value      = {};
    sProcess.options.scouts.InputTypes = {'results'};
    % === SCOUT FUNCTION ===
    sProcess.options.scoutfunc.Comment    = {'Mean', 'Max', 'PCA', 'Std', 'All', 'Scout function:'};
    sProcess.options.scoutfunc.Type       = 'radio_line';
    sProcess.options.scoutfunc.Value      = 1;
    sProcess.options.scoutfunc.InputTypes = {'results'};
    % === SCOUT TIME ===
    sProcess.options.scouttime.Comment    = {'Before', 'After', 'When to apply the scout function:'};
    sProcess.options.scouttime.Type       = 'radio_line';
    sProcess.options.scouttime.Value      = 1;
    sProcess.options.scouttime.InputTypes = {'results'};
    % === ROW NAMES
    sProcess.options.target_tf.Comment    = 'Row names or indices (empty=all): ';
    sProcess.options.target_tf.Type       = 'text';
    sProcess.options.target_tf.Value      = '';
    sProcess.options.target_tf.InputTypes = {'timefreq', 'matrix'};
    % Ignore bad segments
    sProcess.options.ignorebad.Comment    = 'Exclude bad segments and bad channels<BR><FONT color="#707070"><I>(Risks of dimensions mismatch when averaging multiple files)</I></FONT>';
    sProcess.options.ignorebad.Type       = 'checkbox';
    sProcess.options.ignorebad.Value      = 1;
    sProcess.options.ignorebad.InputTypes = {'data', 'raw'};

    % ==== ESTIMATOR ====
    sProcess.options.label_pac.Comment = '<BR><B><U>Estimator options</U></B>:';
    sProcess.options.label_pac.Type    = 'label';
    % === NESTING FREQ
    sProcess.options.nesting.Comment = 'Nesting frequency band (low):';
    sProcess.options.nesting.Type    = 'range';
    sProcess.options.nesting.Value   = {[2, 30], 'Hz', 2};
    % === NESTED FREQ
    sProcess.options.nested.Comment = 'Nested frequency band (high):';
    sProcess.options.nested.Type    = 'range';
    sProcess.options.nested.Value   = {[40, 150], 'Hz', 2};
    % === NESTED FREQ
    sProcess.options.numfreqs.Comment = 'Total number of frequency bins (0=default):';
    sProcess.options.numfreqs.Type    = 'value';
    sProcess.options.numfreqs.Value   = {0, ' ', 0};
    
    % ==== LOOP ====
    sProcess.options.label_loop.Comment = '<BR><B><U>Loop options [expert only]</U></B>:';
    sProcess.options.label_loop.Type    = 'label';
    % === Parallel processing
    sProcess.options.parallel.Comment = 'Use the parallel processing toolbox';
    sProcess.options.parallel.Type    = 'checkbox';
    sProcess.options.parallel.Value   = 0;
    if ~exist('matlabpool', 'file') && ~exist('parpool', 'file')
        sProcess.options.parallel.Hidden = 1;
    end