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_morlet.m
    path of file: ./repos/spm12
    
    the code of the file until where you have to start completion: function [C] = spm_morlet(s,k,wnum)
% Morlet wavelet transform (time-frequency analysis)
% FORMAT [C] = spm_morlet(s,k,wnum)
%
% s      - (t X n) time-series
% k      - Frequencies (cycles per time bin)
% wnum   - Wavelet number: default = 6

    
function [C] = spm_morlet(s,k,wnum)
% Morlet wavelet transform (time-frequency analysis)
% FORMAT [C] = spm_morlet(s,k,wnum)
%
% s      - (t X n) time-series
% k      - Frequencies (cycles per time bin)
% wnum   - Wavelet number: default = 6
%
% C      - coefficents (complex)
%__________________________________________________________________________
%
% This routine returns a Morlet-like wavelet transform but uses a Hanning
% window, as opposed to a Gaussian window.
%__________________________________________________________________________
% Copyright (C) 2008 Wellcome Trust Centre for Neuroimaging

% Karl Friston
% $Id: spm_morlet.m 6122 2014-07-25 13:48:47Z karl $


% setup and defaults
%--------------------------------------------------------------------------
if nargin < 3, wnum = 6;          end