ExecutionFunctions.swift

// Execution Functions
  private func turnExteriorLightsOn()
  {
    leftFrontLight .isOn = true
    rightFrontLight.isOn = true
    leftBackLight  .isOn = true
    rightBackLight .isOn = true
  }
  private func checkForBurnedBulbs()
  {
     for lightBulb in bulbs where !lightBulb.isUseable
     {
       Dashborad.display(errorType: .lights)
       break
     } 
  }