input: from typing import List
  
  def find_primes(n: int) -> List[int]:
      """Find all prime numbers up to a given integer n.
      >>> find_primes(10)
      [2, 3, 5, 7]
      >>> find_primes(20)
      [2, 3, 5, 7, 11, 13, 17, 19]
      """
      primes = []
      for num in range(2, n + 1):
          if all(num % i != 0 for i in range(2, int(num ** 0.5) + 1)):
              primes.append(num)
      return primes
output:     primes = []
      for num in range(2, n + 1):
          if all(num % i != 0 for i in range(2, int(num ** 0.5) + 1)):
              primes.append(num)
      return primes