input: from typing import List
  
  def is_prime(num: int) -> bool:
      """Check if a number is a prime number.
      >>> is_prime(5)
      True
      >>> is_prime(6)
      False
      """
      for i in range(2, int(num ** 0.5) + 1):
          if num % i == 0:
              return False
      return True
  
  def find_primes(n: int) -> List[int]:
      """Find all prime numbers up to a given number n.
      >>> find_primes(10)
      [2, 3, 5, 7]
      >>> find_primes(20)
      [2, 3, 5, 7, 11, 13, 17, 19]
      """
      primes = []
      for number in range(2, n + 1):
          if is_prime(number):
              primes.append(number)
      return primes
output:     primes = []
      for number in range(2, n + 1):
          if is_prime(number):
              primes.append(number)
      return primes