Buggy python submission (verdict: Runtime Error):
#!/usr/bin/env python3
import sys


def solve(M: int, K: int):
    if M == 0:
        if K == 0:
            print('0 0')
        else:
            print(-1)
    elif M == 1:
        if K == 0:
            print('0 0 1 1')
        else:
            print(-1)
    else:
        if K > 2 ** M:
            print(-1)
        else:
            l = list(map(str, list(range(2 ** M))))
            l.pop(K)
            print(' '.join(l), end=' ')
            print(K, end=' ')
            print(' '.join(l[::-1]), end=' ')
            print(K)
    return


# Generated by 1.1.5 https://github.com/kyuridenamida/atcoder-tools
# (tips: You use the default template now. You can remove this line by using your custom template)
def main():
    def iterate_tokens():
        for line in sys.stdin:
            for word in line.split():
                yield word
    tokens = iterate_tokens()
    M = int(next(tokens))  # type: int
    K = int(next(tokens))  # type: int
    solve(M, K)


if __name__ == '__main__':
    main()


Fixed submission:
#!/usr/bin/env python3
import sys


def solve(M: int, K: int):
    if M == 0:
        if K == 0:
            print('0 0')
        else:
            print(-1)
    elif M == 1:
        if K == 0:
            print('0 0 1 1')
        else:
            print(-1)
    else:
        if K >= 2 ** M:
            print(-1)
        else:
            ans = [i for i in range(2 ** M) if i != K]
            ans = ans + [K] + ans[::-1] + [K]
            print(*ans)
    return


# Generated by 1.1.5 https://github.com/kyuridenamida/atcoder-tools
# (tips: You use the default template now. You can remove this line by using your custom template)
def main():
    def iterate_tokens():
        for line in sys.stdin:
            for word in line.split():
                yield word
    tokens = iterate_tokens()
    M = int(next(tokens))  # type: int
    K = int(next(tokens))  # type: int
    solve(M, K)


if __name__ == '__main__':
    main()

Buggy python submission (verdict: Runtime Error):
#!/usr/bin/env python3
import sys


def solve(M: int, K: int):
    if M == 0:
        if K == 0:
            print('0 0')
        else:
            print(-1)
    elif M == 1:
        if K == 0:
            print('0 0 1 1')
        else:
            print(-1)
    else:
        if K > 2 ** M:
            print(-1)
        else:
            l = list(range(2 ** M))
            l.pop(K)
            print(' '.join(l), end=' ')
            print(K, end=' ')
            print(' '.join(l[::-1]), end=' ')
            print(K)
    return


# Generated by 1.1.5 https://github.com/kyuridenamida/atcoder-tools
# (tips: You use the default template now. You can remove this line by using your custom template)
def main():
    def iterate_tokens():
        for line in sys.stdin:
            for word in line.split():
                yield word
    tokens = iterate_tokens()
    M = int(next(tokens))  # type: int
    K = int(next(tokens))  # type: int
    solve(M, K)


if __name__ == '__main__':
    main()


Fixed submission:
#!/usr/bin/env python3
import sys


def solve(M: int, K: int):
    if M == 0:
        if K == 0:
            print('0 0')
        else:
            print(-1)
    elif M == 1:
        if K == 0:
            print('0 0 1 1')
        else:
            print(-1)
    else:
        if K >= 2 ** M:
            print(-1)
        else:
            ans = [i for i in range(2 ** M) if i != K]
            ans = ans + [K] + ans[::-1] + [K]
            print(*ans)
    return


# Generated by 1.1.5 https://github.com/kyuridenamida/atcoder-tools
# (tips: You use the default template now. You can remove this line by using your custom template)
def main():
    def iterate_tokens():
        for line in sys.stdin:
            for word in line.split():
                yield word
    tokens = iterate_tokens()
    M = int(next(tokens))  # type: int
    K = int(next(tokens))  # type: int
    solve(M, K)


if __name__ == '__main__':
    main()