The indentation is broken, so one possible way to interpret it is:

  def is_prime(n: int):
      result = True
      for k in range(2, int(n ** 0.5) + 1):
          if n % k == 0:
              result = False
          break
      return result

Which is just a more complicated (n % 2 != 0). Obviously the break should be in the if block.