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: canlab_glm_group_levels.m
    path of file: ./repos/CanlabCore/CanlabCore/GLM_Batch_tools
    
    the code of the file until where you have to start completion: function canlab_glm_group_levels(
    
function announce_string(string)

s = sprintf('--  %s  --',string);
l = regexprep(s,'.','-');
fprintf('> \n> \n> \n> %s\n> %s\n> %s\n> \n',l,s,l);

end