input: from typing import List
  
  def remove_duplicates(numbers: List[int]) -> List[int]:
      """ Removes all duplicate elements from a given list of integers.
      >>> remove_duplicates([1, 2, 3, 2, 4, 5, 6, 3])
      [1, 2, 3, 4, 5, 6]
      >>> remove_duplicates([5, 5, 5, 5])
      [5]
      """
      final_list = []
      for num in numbers:
          if num not in final_list:
              final_list.append(num)
      return final_list
output:     final_list = []
      for num in numbers:
          if num not in final_list:
              final_list.append(num)
      return final_list