def complex_evaluation(tokens):
    brackets = ["(", "[", "{", ")", "]", "}"]
    bracketsclose = [")", "]", "}"]
    bracketsopen = ["(", "[", "{"]
    brackpos = []
    for i in range(len(tokens)):
        if tokens[i] in brackets:
            brackpos.append([tokens[i], i])
    while len(brackpos) != 0:
        last = brackpos[0][1]
        for i in brackpos:
            if i[0] in bracketsclose:
                x = simple_evaluation(tokens[last + 1:i[1]])
                del tokens[last:i[1] + 1]
                tokens.insert(last, x)
            last = i[1]
            print(tokens)


complex_evaluation([2, "^", "[", 4, "*", "(", 4, "+", 5, ")", "]", "/", 4])