input: Write a function to remove all duplicate elements from a list while preserving the original order. If the given list is empty, return an empty list.
  def remove_duplicates(nums):
   new_list = []
   for num in nums:
   if num not in newlist:
   new_list.append(num)
   
   return new_list
  assert remove_duplicates([1, 3, 3, 5, 5, 7])==[1, 3, 5, 7]
  assert remove_duplicates([3, 3, 3, 3])==[3]
  assert remove_duplicates([1, 2, 3, 4])==[1, 2, 3, 4]
  assert remove_duplicates([])==[]
  assert remove_duplicates([5])==[5]
output: def remove_duplicates(nums):
      new_list = []
      for num in nums:
          if num not in new_list:
              new_list.append(num)
      return new_list