input: Write a python function to print a specific pattern of stars.
  assert print_pattern() == """ ** ** 
  *  *  *
  *     *
   *   * 
    * *  
     *   """
output: def print_pattern():
      pattern = """ ** ** 
  *  *  *
  *     *
   *   * 
    * *  
     *   """
      return pattern