input: Write a function to determine if the given array has an even or odd number of elements. If the number of elements is even, return True, else return False. If the array is empty, return True as an empty array can be considered to have an even number of elements.
  
  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([1, 2, 3])==False
  assert is_array_even([])==True
output: def is_array_even(arr): 
    if len(arr)%2 == 0:
      return True
    else:
      return False