new_contents: from modules.fib import fib
  
  def test_fib_zero():
      assert fib(0) == 0 
  
  def test_fib_one():
      assert fib(1) == 1 
  
  def test_fib_three():
      assert fib(3) == 2
      assert fib(3) == fib(1) + fib(2)
      assert fib(3) == fib(1) + fib(1) + fib(0)
  
subject: add tests