from ordered_hash_set import OrderedSet

s = OrderedSet()

s.add("London")
s.add("Tokyo")
# you can add multiple entries at once, like this:
s.update("Paris", "Istanbul")
s.add("London")
s.remove("Tokyo")

print(s) # prints: OrderedSet(London, Paris, Istanbul)

# Thanks to the hashing. Time complexity of checking
# if an element present in a collection is O(1).
# Which is faster than regular list: O(n).
if "Paris" in s:
  print("Paris is in the set.")

# It is also possible, but not recommended due to inefficiency,
# to get the item by index:
assert s[2] == "Istanbul"