input: Write a function to determine if the number of elements in an array is even or odd. If the number of elements is even, return True; otherwise, return False.
  def is_array_even(arr): 
    if len(arr)%2 == 0:
      return True
    else:
      return False
  assert is_array_even([1, 2, 3, 4])==True
  assert is_array_even([5, 6, 7])==False
output: def is_array_even(arr): 
    if len(arr)%2 == 0:
      return True
    else:
      return False