input: 
  def is_array_even(arr: List[int]) -> bool:
      """ Check if the given array has an even number of elements.
      >>> is_array_even([1, 2, 3, 4])
      True
      >>> is_array_even([1, 2, 3])
      False
      """
  
output:     return len(arr) % 2 == 0