Python how to re-list three ways Python list deduplication

1. to re-list

li = []
for item in my_list:
    if item not in li:
        li.append(item)

2. collection deduplication

list(set(my_list))

3. dictionary deduplication

dict1 = dict.fromkeys(my_list, '')
li = dict1.keys

 https://www.cnblogs.com/delav/p/9364244.html