Formatting Dictionary items and writing them to a file

def dict2file(d, filename):
    D1, D2 = dict(), dict()

    for i in d:
        if isinstance(i, int):
            D1[i] = d[i]
        else:
            D2[i] = d[i]

    with open(f"{filename}.txt", "w") as file:
        L1, L2 = sorted(D1.items()), sorted(D2.items())

        if any(L1):
            for i in L1:
                file.write(f"{i[0]} -> {i[1]}\n")

        elif any(L2):
            for i in L2:
                file.write(f"{i[0]} -> {i[1]}\n")

    print("File Written Successfully")

d = {"12": 2,"11": 1,"A":31,'a': 30,'c': 1,'b': 17,'e': 9,'d': 52,'f': 11,
    'g': 1,'h': 23,'13': 16,'k': 2,'l': 8}
dict2file(d, "filename")