input: def deleteDuplicates(numbers: List[float]) -> List[float]:
      """ Deletes all duplicates in a given list of numbers.
      >>> deleteDuplicates([1.0, 2.0, 3.0, 2.0, 4.0])
      [1.0, 2.0, 3.0, 4.0]
      >>> deleteDuplicates([1.0, 1.0, 1.0])
      [1.0]
      """
output:     seen = set()
      result = []
      for num in numbers:
          if num not in seen:
              seen.add(num)
              result.append(num)
      return result