input: Write a python function to find all prime numbers in a range and return them as a list.
  assert prime_numbers(10) == [2, 3, 5, 7]
  assert prime_numbers(20) == [2, 3, 5, 7, 11, 13, 17, 19]
  assert prime_numbers(5) == [2, 3, 5]
output: def prime_numbers(n):
      def is_prime(x):
          if x < 2:
              return False
          for i in range(2, int(x**0.5) + 1):
              if x % i == 0:
                  return False
          return True
      
      return [x for x in range(2, n+1) if is_prime(x)]