input: Write a function to print out the first n prime numbers. If the input is 0, the function should return an empty list.
  assert sieve_of_eratosthenes(0)==[]
  assert sieve_of_eratosthenes(5)==[2, 3, 5, 7, 11]
  assert sieve_of_eratosthenes(10)==[2, 3, 5, 7, 11, 13, 17, 19, 23, 29]
  assert sieve_of_eratosthenes(1)==[2]
  assert sieve_of_eratosthenes(2)==[2, 3]
output: def sieve_of_eratosthenes(n):
      if n == 0:
          return []
      primes = []
      num = 2
      while len(primes) < n:
          is_prime = True
          for prime in primes:
              if num % prime == 0:
                  is_prime = False
                  break
          if is_prime:
              primes.append(num)
          num += 1
      return primes