input: Write a python function to remove duplicate items from a list.
  assert remove_duplicates(["Apple", "Pear", "Apple", "Banana", "Pear"]) == ["Apple", "Pear", "Banana"]
  assert remove_duplicates([1, 2, 2, 3, 4, 4, 5]) == [1, 2, 3, 4, 5]
  assert remove_duplicates(["a", "b", "a", "c", "b", "d"]) == ["a", "b", "c", "d"]
output: def remove_duplicates(lst):
      seen = set()
      result = []
      for item in lst:
          if item not in seen:
              seen.add(item)
              result.append(item)
      return result