Return unique elements preserving first occurrence order. Example: [3,1,2,1,3,4] => [3,1,2,4]
Implement this function:
def unique_in_order(lst: list) -> list:
Write the function only — the arguments are read for you and the return value is printed automatically.
Arguments arrive as one Python literal per line, in this order: lst.
Input
[3, 1, 2, 1, 3, 4]
Output
[3, 1, 2, 4]