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: spm_dcm_tfm_data.m
    path of file: ./repos/spm12/toolbox/dcm_meeg
    
    the code of the file until where you have to start completion: function DCM = spm_dcm_tfm_data(DCM)
% gets cross-spectral density data-features using a wavelet transform
% FORMAT DCM = spm_dcm_tfm_data(DCM)
% DCM    -  DCM structure
% requires
%
%    DCM.xY.Dfile        - name of data file
%    DCM.M.U             - channel subspace
%    DCM.options.trials  - trial to evaluate
%    DCM.options.Tdcm    - time limits
%    DCM.options.Fdcm    - frequency limits
%    DCM.options.D       - Down-sampling
%
% sets
%
%    DCM.xY.pst     - Peristimulus Time [ms] sampled
%    DCM.xY.dt      - sampling in seconds [s] (down-sampled)
%    DCM.xY.U       - channel subspace
%    DCM.xY.y       - cross spectral density over channels
%    DCM.xY.csd     - cross spectral density over channels
%    DCM.xY.erp     - event-related average over channels
%    DCM.xY.It      - Indices of time bins
%    DCM.xY.Ic      - Indices of good channels
%    DCM.xY.Hz      - Frequency bins
%    DCM.xY.code    - trial codes evaluated
%    DCM.xY.scale   - scalefactor applied to data
%    DCM.xY.Rft     - Wavelet number or ratio of frequency to time
%__________________________________________________________________________
% Copyright (C) 2008 Wellcome Trust Centre for Neuroimaging
 

    
function DCM = spm_dcm_tfm_data(DCM)
% gets cross-spectral density data-features using a wavelet transform
% FORMAT DCM = spm_dcm_tfm_data(DCM)
% DCM    -  DCM structure
% requires
%
%    DCM.xY.Dfile        - name of data file
%    DCM.M.U             - channel subspace
%    DCM.options.trials  - trial to evaluate
%    DCM.options.Tdcm    - time limits
%    DCM.options.Fdcm    - frequency limits
%    DCM.options.D       - Down-sampling
%
% sets
%
%    DCM.xY.pst     - Peristimulus Time [ms] sampled
%    DCM.xY.dt      - sampling in seconds [s] (down-sampled)
%    DCM.xY.U       - channel subspace
%    DCM.xY.y       - cross spectral density over channels
%    DCM.xY.csd     - cross spectral density over channels
%    DCM.xY.erp     - event-related average over channels
%    DCM.xY.It      - Indices of time bins
%    DCM.xY.Ic      - Indices of good channels
%    DCM.xY.Hz      - Frequency bins
%    DCM.xY.code    - trial codes evaluated
%    DCM.xY.scale   - scalefactor applied to data
%    DCM.xY.Rft     - Wavelet number or ratio of frequency to time
%__________________________________________________________________________
% Copyright (C) 2008 Wellcome Trust Centre for Neuroimaging
 
% Karl Friston
% $Id: spm_dcm_tfm_data.m 7749 2019-12-05 17:05:46Z guillaume $
 
% Set defaults and Get D filename
%-------------------------------------------------------------------------
try
    Dfile = DCM.xY.Dfile;
catch
    errordlg('Please specify data and trials');
    error('')
end