title: matlab function with argument not required
body: <p>I create a function </p>
  
  <pre><code>function y = getValue(modelName, param, option)
      open_system(modelName);
      runModel(option);
      y = getActiveFun(param);
  end
  </code></pre>
  
  <p>I would like when calling this function to have the choice to pass or not argument <code>option</code>
  from some other files I call the function with all arguments and sometimes I would like to call it without passing <code>option</code> argument ?</p>
  
  <p>I would like to call : <code>getValue(modelName, param)</code> from other files</p>
  
  <p>How could I do that ?</p>