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: ft_combineplanar.m
    path of file: ./repos/fecgsyn/subfunctions/data-generation/libs/fieldtrip
    
    the code of the file until where you have to start completion: function [data] = ft_combineplanar(cfg, data)

% FT_COMBINEPLANAR computes the planar gradient magnitude over both directions
% combining the two gradients at each sensor to a single positive-valued number. This
% can be done for single-trial/averaged planar gradient ERFs or single-trial/averaged

    
function [data] = ft_combineplanar(cfg, data)

% FT_COMBINEPLANAR computes the planar gradient magnitude over both directions
% combining the two gradients at each sensor to a single positive-valued number. This
% can be done for single-trial/averaged planar gradient ERFs or single-trial/averaged
% TFRs.
%
% Use as
%   [data] = ft_combineplanar(cfg, data)
% where data contains an averaged planar-gradient ERF or single-trial or
% averaged TFRs.
%
% The configuration can contain
%   cfg.method         = 'sum', 'svd', 'abssvd', or 'complex' (default = 'sum')
%   cfg.updatesens     = 'no' or 'yes' (default = 'yes')
% and for timelocked input data (i.e. ERFs), the configuration can also contain
%   cfg.demean         = 'yes' or 'no' (default = 'no')
%   cfg.baselinewindow = [begin end