Best / most pythonic way to get an ordered list of unique items

Question

I have one or more unordered sequences of (immutable, hashable) objects with possible duplicates and I want to get a sorted sequence of all those objects without duplicates.

Right now I'm using a set to quickly gather all the elements discarding duplicates, convert it to a list and then sort that:

result = set()
for s in sequences:
    result = result.union(s)
result = list(result)
result.sort()
return result

It works but I wouldn't call it "pretty". Is there a better way?

Answer 1

This should work:

sorted(set(itertools.chain.from_iterable(sequences)))