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: import_xml2session.m
    path of file: ./repos/CellExplorer/calc_CellMetrics
    
    the code of the file until where you have to start completion: function session = import_xml2session(xml_file,session)
% Imports channel groups from .xml file to sesssion struct

% By Peter Petersen
% petersen.peter@gmail.com

    
function session = import_xml2session(xml_file,session)
% Imports channel groups from .xml file to sesssion struct

% By Peter Petersen
% petersen.peter@gmail.com
% Last edited: 16-03-2020

if nargin<2
    session = [];
end