AOC day 6

#!/usr/bin/env python3

def find_marker(buffer, dch=4):
    for i in range(len(buffer)):
        if dch == len(set(buffer[i:i+dch])):
            break
    return i+dch

assert(find_marker("mjqjpqmgbljsphdztnvjfqwrcgsmlb")==7)
assert(find_marker("bvwbjplbgvbhsrlpgdmjqwftvncz")==5)
assert(find_marker("nppdvjthqldpwncqszvftbrmjlhg")==6)
assert(find_marker("nznrnfrfntjfmvfwmzdfjlvtqnbhcprsg")==10)
assert(find_marker("zcfzfwzzqfrljwzlrfnpqdbhtmscgvjw")==11)
print("PASS")
print("Part 1:", find_marker(open("input.txt").read()),"\n\n")

assert(find_marker("mjqjpqmgbljsphdztnvjfqwrcgsmlb",dch=14)==19)
assert(find_marker("bvwbjplbgvbhsrlpgdmjqwftvncz", dch=14)==23)
assert(find_marker("nppdvjthqldpwncqszvftbrmjlhg", dch=14)==23)
assert(find_marker("nznrnfrfntjfmvfwmzdfjlvtqnbhcprsg", dch=14)==29)
assert(find_marker("zcfzfwzzqfrljwzlrfnpqdbhtmscgvjw", dch=14)==26)
print("PASS")
print("Part 2:", find_marker(open("input.txt").read(),dch=14))