input: 
  def removeDuplicates(array):
      """Removes duplicates from a given list using built-in functions.
      
      >>> removeDuplicates([1, 2, 3, 3, 4, 5, 5, 6])
      [1, 2, 3, 4, 5, 6]
      >>> removeDuplicates([10, 10, 20, 20, 30, 30])
      [10, 20, 30]
      >>> removeDuplicates([1, 2, 3, 4, 5])
      [1, 2, 3, 4, 5]
      """
      return list(dict.fromkeys(array))
  
output:     return list(dict.fromkeys(array))