How can I get unique arrays in Python?

I got a fairly large array of arrays of length 2 (List[List[int, int]])
How can I unique arrays of them? Preferably without using different libraries

I’ve seen several solutions that use numpy, but I’m unlikely to be able to use this in olympiads

# Example input:
nums = [[2, 9], [3, 6], [9, 2], [6, 3]]

for i in nums:
    # some code here

# Output:
# nums = [[2, 9], [3, 6]]

I tried doing this but I guess it’s not a very fast solution

# Example input:
nums = [[2, 9], [3, 6], [9, 2], [6, 3]]

unique = []
for i in nums:
    if sorted(i) not in unique:
        unique.append(sorted(i))

# Output:
print(unique) # [[2, 9], [3, 6]]

>Solution :

To deal with sets not being hashable, you can create a set of frozensets this way:

unique = {frozenset(i) for i in nums}

Then you can use whichever means to turn the results into the objects you want; for example:

unique = [list(i) for i in unique]