input: Write a function to delete all duplicates in a given list of numbers. The function should return a new list with unique elements in the order they first appeared. The function should take a list as input and return the modified list.
  assert deleteDuplicates([1, 2, 2, 3, 4, 4, 5]) == [1, 2, 3, 4, 5]
  assert deleteDuplicates([5, 5, 5, 5]) == [5]
  assert deleteDuplicates([]) == []
  assert deleteDuplicates([1, 2, 3, 4, 5]) == [1, 2, 3, 4, 5]
output: def deleteDuplicates(nums):
      seen = set()
      result = []
      for num in nums:
          if num not in seen:
              seen.add(num)
              result.append(num)
      return result