input: from typing import List
  
  def removeDuplicates(array: List[int]) -> List[int]:
      """Remove duplicates from the given array using built-in functions.
      >>> removeDuplicates([1, 2, 3, 2, 1])
      [1, 2, 3]
      >>> removeDuplicates([4, 5, 6, 5, 4])
      [4, 5, 6]
      """
output:     return list(dict.fromkeys(array))