input: def generate_prime_numbers(n: int) -> None:
      """ Generates and prints all prime numbers less than or equal to n.
      >>> generate_prime_numbers(10)
      2
      3
      5
      7
      >>> generate_prime_numbers(20)
      2
      3
      5
      7
      11
      13
      17
      19
      """
output:     if n < 2:
          return
      primes = [True] * (n + 1)
      primes[0] = primes[1] = False
      for i in range(2, int(n**0.5) + 1):
          if primes[i]:
              for j in range(i*i, n + 1, i):
                  primes[j] = False
      for i in range(2, n + 1):
          if primes[i]:
              print(i)