Advent of Code Day 17 part 2

with open("2023_17input.txt", 'r') as file:
    my_input = file.read()

raw_data = my_input

grid = raw_data.split('\n')

start_position = (0, 0)
end_position = (len(grid[0]) - 1, len(grid) - 1)

ways = {
    'r': (1, 0),
    'd': (0, 1),
    'l': (-1, 0),
    'u': (0, -1),
    }

min_cooling = len(grid) * len(grid[0]) * 9

def add_pos(a, b):
    return tuple([x+y for x, y in zip(a, b)])

def find_cooling(x, y):
    return int(grid[y][x])

def vet_way(way, pos, lastmoves):
    # possible objections:
    # - being the eleventh in a row that's the same
    if lastmoves:
        if len(lastmoves) == 10 and lastmoves[-1] == way:
            return False
    # - not having gone four moves in the same direction yet
        elif len(lastmoves) < 4 and lastmoves[-1] != way:
            return False
    # - going back on yourself
        if add_pos(ways[way], ways[lastmoves[-1]]) == (0, 0):
            return False
    new_pos = add_pos(ways[way], pos)
    # - going out of bounds
    if new_pos[0] < 0 or new_pos[0] > len(grid[0]) - 1:
        return False
    if new_pos[1] < 0 or new_pos[1] > len(grid) - 1:
        return False
    return True

# make massive dictionary of every possible travel state at every position
records = {}
 for y in range(len(grid)):
    for x in range(len(grid[0])):
        for i in range(1, 11):
            for way in ways:
                records[((x, y), way*i)] = min_cooling


records[((start_position), "")] = 0

# start at the starting point with count 0 and no moves made
changes = {(start_position, "")}

while changes:
    print(len(changes))
    new_changes = set()
    for pos, lastmoves in changes:
        if pos == end_position:
            pass
        else:
            for way in ways:
                if vet_way(way, pos, lastmoves):
                    new_pos = add_pos(pos, ways[way])
                    newcooling = records[(pos, lastmoves)] + find_cooling(*new_pos)
                    if way in lastmoves:
                        next_moves = lastmoves + way
                    else:
                        next_moves = way
                    if records[(new_pos, next_moves)] > newcooling:
                        new_changes.add((new_pos, next_moves))
                        records[(new_pos, next_moves)] = newcooling
    changes = new_changes

for record in records:
    # remember to make sure you've done at least four moves
    # in the current direction, otherwise test input 2 fails
    if record[0] == end_position and len(record[1]) > 3:
        if records[record] < min_cooling:
            min_cooling = records[record]
print(min_cooling)