input: 
  def create_square_dict(numbers: List[int]) -> dict:
      """ Create a dictionary that maps each number in the list to its square.
      >>> create_square_dict([1, 2, 3])
      {1: 1, 2: 4, 3: 9}
      >>> create_square_dict([5, 10, 15, 20])
      {5: 25, 10: 100, 15: 225, 20: 400}
      """
  
output:     result = {}
      for num in numbers:
          result[num] = num ** 2
      return result