input: Write a function to optimize the given Python code to use built-in functions for removing duplicates from an array. If the given array is empty return an empty list.
  def removeDuplicates(array):
      return list(dict.fromkeys(array))
  
  assert removeDuplicates([1, 2, 2, 3, 4, 4])==[1, 2, 3, 4]
  assert removeDuplicates([5, 5, 5, 5])==[5]
  assert removeDuplicates([1, 2, 3, 4])==[1, 2, 3, 4]
  assert removeDuplicates([])==[]
output: def removeDuplicates(array):
      return list(dict.fromkeys(array))