input: Write a function to filter out prime numbers from a given list of integers and return a sublist containing only the prime numbers. If the input list is empty, return an empty list.
  def is_prime(num):
   for i in range(2, num // 2 + 1):
   if num % i == 0:
   return False
   return True
  
  def prime_list(lst):
   prime_lst = []
   for num in lst:
   if is_prime(num):
   prime_lst.append(num)
   return prime_lst
  
  assert prime_list([2, 8, 3, 6, 10, 7, 14, 11, 17, 15])==[2, 3, 7, 11, 17]
  assert prime_list([])==[]
output: def prime_list(lst):
      def is_prime(num):
          if num < 2:
              return False
          for i in range(2, int(num**0.5) + 1):
              if num % i == 0:
                  return False
          return True
      
      return [num for num in lst if is_prime(num)]