old_contents: def sieve(n):
      if n < 2:
          return []
      not_prime = set()
      prime = [2]
      for i in range(3, n+1, 2):
          if i not in not_prime:
              prime.append(i)
              not_prime.update(range(i*i, n, i))
      return prime
  
new_contents: def sieve(n):
      if n < 2:
          return []
      not_prime = set()
      prime = [2]
      for i in range(3, n+1, 2):
          if i not in not_prime:
              prime.append(i)
              not_prime.update(range(i*i, n+1, i))
      return prime
  
subject: Fix bug where n is the square of a prime