input: Write a function to remove all duplicate elements from a given list while preserving the original order. The function should take a list of integers as its argument and return a new list with all duplicates removed.
  
  def remove_duplicates(nums):
      new_list = []
      for num in nums:
          if num not in new_list:
              new_list.append(num)
      return new_list
  
  assert remove_duplicates([1, 3, 3, 5, 5, 7]) == [1, 3, 5, 7]
  assert remove_duplicates([2, 4, 4, 6, 8, 8]) == [2, 4, 6, 8]
  assert remove_duplicates([10, 15, 15, 20, 25, 25]) == [10, 15, 20, 25]
  assert remove_duplicates([]) == []
  assert remove_duplicates([1, 1, 1, 1]) == [1]
output: def remove_duplicates(nums):
      new_list = []
      for num in nums:
          if num not in new_list:
              new_list.append(num)
      return new_list