input: Write a function to reverse the order of the integer values in the given array. If the array is empty, return an empty array.
  assert reverse_array([1, 2, 3, 4, 5])==[5, 4, 3, 2, 1]
  assert reverse_array([10, 20, 30])==[30, 20, 10]
  assert reverse_array([])==[]
output: def reverse_array(arr):
      return arr[::-1]