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_electroderealign.m
    path of file: ./repos/bspm/thirdparty/spm12/external/fieldtrip
    
    the code of the file until where you have to start completion: function [elec_realigned] = ft_electroderealign(cfg, elec_original)

% FT_ELECTRODEREALIGN rotates, translates, scales and warps electrode positions. The
% default is to only rotate and translate, i.e. to do a rigid body transformation in
% which only the coordinate system is changed. With the right settings if can apply
% additional deformations to the input sensors (e.g. scale them to better fit the
% skin surface). The different methods are described in detail belo
    
function
cfg = ft_checkconfig(cfg, 'renamed',    {'template', 'target'});
cfg = ft_checkconfig(cfg, 'renamedval', {'method', 'realignfiducials', 'fiducial'});
cfg = ft_checkconfig(cfg, 'renamedval', {'method', 'realignfiducial',  'fiducial'});
cfg = ft_checkconfig(cfg, 'renamedval', {'warp', 'homogenous', 'rigidbody'});
cfg = ft_checkconfig(cfg, 'renamedval', {'warp', 'homogeneous', 'rigidbody'});
cfg = ft_checkconfig(cfg, 'forbidden', 'outline');

% set the defaults
cfg.warp          = ft_getopt(cfg, 'warp', 'rigidbody');
cfg.channel       = ft_getopt(cfg, 'channel',  'all');
cfg.keepchannel   = ft_getopt(cfg, 'keepchannel', 'no');
cfg.feedback      = ft_getopt(cfg, 'feedback', 'no');
cfg.casesensitive = ft_getopt(cfg, 'casesensitive', 'no');
cfg.headshape     = ft_getopt(cfg, 'headshape', []);     % for triangulated head surface, without labels
cfg.target        = ft_getopt(cfg, 'target',  []);       % for electrodes or fiducials, always with labels
cfg.coordsys      = ft_getopt(cfg, 'coordsys');          % this allows for automatic template fiducial placement

if isempty(cfg.target)
  % remove the field, otherwise ft_checkconfig will complain
  cfg = rmfield(cfg, 'target');
end