input: 
  def get_even_numbers(start: int, end: int) -> List[int]:
      """ Returns a list of even numbers between `start` (inclusive) and `end` (exclusive).
      >>> get_even_numbers(1, 21)
      [2, 4, 6, 8, 10, 12, 14, 16, 18, 20]
      """
  
output:     result = []
      for num in range(start, end):
          if num % 2 == 0:
              result.append(num)
      return result