input: Write a function to shuffle an array of integers using Python's random module. The function should return the shuffled array.
  
  ### Input:
  [1, 5, 9, 4, 2]
  
  ### Output:
  import random
  
  def shuffle_array(arr):
      random.shuffle(arr)
      return arr
  
  assert shuffle_array([1, 5, 9, 4, 2]) != [1, 5, 9, 4, 2]
  assert len(shuffle_array([1, 5, 9, 4, 2])) == 5
  assert all(elem in shuffle_array([1, 5, 9, 4, 2]) for elem in [1, 5, 9, 4, 2])
output: import random
  
  def shuffle_array(arr):
      random.shuffle(arr)
      return arr