input: from typing import List
  
  def deleteDuplicates(nums: List[int]) -> List[int]:
      """ Deletes all duplicates in a given list of numbers.
      >>> deleteDuplicates([1, 2, 3, 1, 2, 3])
      [1, 2, 3]
      >>> deleteDuplicates([5, 6, 5, 7, 6, 8])
      [5, 6, 7, 8]
      """
output:     seen = set()
      result = []
      for num in nums:
          if num not in seen:
              seen.add(num)
              result.append(num)
      return result