input: from typing import List
  
  def remove_duplicates(nums: List[int]) -> List[int]:
      """Remove all duplicate elements from a list and preserve the original order.
      >>> remove_duplicates([1, 3, 3, 5, 5, 7])
      [1, 3, 5, 7]
      >>> remove_duplicates([2, 2, 2, 2])
      [2]
      """
      new_list = []
      for num in nums:
          if num not in new_list:
              new_list.append(num)
      return new_list
output:     new_list = []
      for num in nums:
          if num not in new_list:
              new_list.append(num)
      return new_list