input: Write a function to remove all duplicate elements from a list while preserving the original order.
  
  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, 2, 2, 2, 2]) == [2]
  assert remove_duplicates([1, 2, 3, 4, 5]) == [1, 2, 3, 4, 5]
  assert remove_duplicates([]) == []
output: def remove_duplicates(nums):
      new_list = []
      for num in nums:
          if num not in new_list:
              new_list.append(num)
      return new_list