input: from typing import List
  
  def removeDuplicates(input: List[int]) -> List[int]:
      """ Remove duplicate entries from a list.
      >>> removeDuplicates([1, 2, 2, 3, 3, 4])
      [1, 2, 3, 4]
      >>> removeDuplicates([5, 5, 5, 5])
      [5]
      """
output:     seen = set()
      result = []
      for num in input:
          if num not in seen:
              seen.add(num)
              result.append(num)
      return result