input: Write a function named `remove_duplicates` that accepts a list of integers and returns a new list with all duplicate elements removed. If the input list is empty, the function should return an empty list.
  
  assert remove_duplicates([1, 2, 3, 2, 4, 5, 6, 3]) == [1, 2, 3, 4, 5, 6]
  assert remove_duplicates([]) == []
output: def remove_duplicates(lst):
      return list(dict.fromkeys(lst))