input: Write a function to left rotate an array by d positions.
  assert left_rotate_array([1, 2, 3, 4, 5], 2) == [3, 4, 5, 1, 2]
  assert left_rotate_array([1, 2, 3, 4, 5], 3) == [4, 5, 1, 2, 3]
  assert left_rotate_array([1, 2, 3, 4, 5], 5) == [1, 2, 3, 4, 5]
  assert left_rotate_array([1, 2, 3, 4, 5], 0) == [1, 2, 3, 4, 5]
output: def left_rotate_array(arr, d):
      n = len(arr)
      d = d % n  # In case d is larger than n
      return arr[d:] + arr[:d]