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: DATA_COVID_UK.m
    path of file: ./repos/spm/toolbox/DEM
    
    the code of the file until where you have to start completion: function [Y,R] = DATA_COVID_UK(country)
% Data retrieval function for COVID modelling (UK)
% FORMAT [Y,R] = DATA_COVID_UK(country)
%
% Y  - daily deaths and confirmed cases
% R  - daily test rates for the UK
%
% country - optional country
%
% This auxiliary routine retrieves data from comma separated data files
% that can be downloaded from:
% https://github.com/CSSEGISandData/COVID-19/
% https://github.com/tomwhite/covid-19-uk-data
%
%     time_series_covid19_confirmed_global.csv

    
function [Y,R] = DATA_COVID_UK(country)
% Data retrieval function for COVID modelling (UK)
% FORMAT [Y,R] = DATA_COVID_UK(country)
%
% Y  - daily deaths and confirmed cases
% R  - daily test rates for the UK
%
% country - optional country
%
% This auxiliary routine retrieves data from comma separated data files
% that can be downloaded from:
% https://github.com/CSSEGISandData/COVID-19/
% https://github.com/tomwhite/covid-19-uk-data
%
%     time_series_covid19_confirmed_global.csv
%     time_series_covid19_deaths_global.csv
%     time_series_covid19_recovered_global.csv
%     covid-19-tests-uk
%
% It augments these data with population sizes from the United Nations,
% returning the following data structure:
%
% Data(k).country - country
% Data(k).pop     - population size
% Data(k).lat     - latitude
% Data(k).long    - longitude
% Data(k).date    - date when more than one case was reported
% Data(k).cases   - number of cases,  from eight days prior to first cases
% Data(k).death   - number of deaths, from eight days prior to first cases
% Data(k).recov   - number recovered, from eight days prior to first cases
% Data(k).days    - number of days in timeseries
% Data(k).cum     - cumulative number of deaths
%
% Population data from (cite as):
% United Nations, Department of Economic and Social Affairs, Population
% Division (2019). World Population Prospects 2019, Online Edition. Rev. 1.
%
% Please see the main body of the script for a description of the graphical
% outputs provided when the routine is called with at an output argument.
%__________________________________________________________________________
% Copyright (C) 2020 Wellcome Centre for Human Neuroimaging

% Karl Friston
% Copyright (C) 2008-2022 Wellcome Centre for Human Neuroimaging

% https://coronavirus.data.gov.uk/coronavirus-cases_latest.csv
% https://coronavirus.data.gov.uk/coronavirus-deaths_latest.csv


% download data if required
%==========================================================================
url = 'https://github.com/CSSEGISandData/COVID-19/raw/master/csse_covid_19_data/csse_covid_19_time_series/';
urlwrite([url,'time_series_covid19_confirmed_global.csv'],'time_series_covid19_confirmed_global.csv');
urlwrite([url,'time_series_covid19_deaths_global.csv'],   'time_series_covid19_deaths_global.csv');
urlwrite([url,'time_series_covid19_recovered_global.csv'],'time_series_covid19_recovered_global.csv');

url = 'https://raw.githubusercontent.com/tomwhite/covid-19-uk-data/master/data/';
urlwrite([url,'covid-19-totals-uk.csv'],'covid-19-totals-uk.csv');

% defaults
%--------------------------------------------------------------------------
if nargin < 1, country = 'United Kingdom'; end