private IEnumerator RecalculateFrequencies(int level)
{
enemyClass.Recalculate(level);
yield return(null);
enemyWeaponClass.Recalculate(level);
yield return(null);
asteroidClass.Recalculate(level);
yield return(null);
powerupClass.Recalculate(level);
yield return(null);
recalculationFinished = true;
}