text: /*
  You're writing code to control your town's traffic lights. You need a function to handle each change from green, to yellow, to red, and then to green again.
  
  Complete the function that takes a string as an argument representing the current state of the light and returns a string representing the state the light should change to.
  
  For example, update_light('green') should return 'yellow'.
  */
  
  function updateLight(current) {
      return current === 'green' ? 'yellow' : current === 'yellow' ? 'red' : 'green';
     }