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: pop_erpchanedit.m
    path of file: ./repos/erplab/pop_functions
    
    the code of the file until where you have to start completion: % PURPOSE: loads channel location information into an erpset
%
% FORMAT:
%
% ERP = erpchanedit(ERP, filename);
%
%
% Se
    
function is part of ERPLAB Toolbox ***
% Author: Javier Lopez-Calderon && Johanna Kreither
% Center for Mind and Brain
% University of California, Davis,
% Davis, CA
% 2013

function [ERP, erpcom] = pop_erpchanedit(ERP, filename, varargin)
erpcom = '';
if nargin<1
        help erpchanedit
        return
end