input: Write a function to generate a prime number sequence using Python. If the given integer n is positive, the function should print all prime numbers less than or equal to n. If n is not positive, return an empty list and print nothing. 
  assert generate_prime_numbers(10) == None
output: def generate_prime_numbers(n):
      if n <= 0:
          return []
      primes = []
      for num in range(2, n + 1):
          for i in range(2, int(num**0.5) + 1):
              if num % i == 0:
                  break
          else:
              primes.append(num)
      print(primes)