Create a Python function calculating the confidence interval for the mean value if you know - the sample size (n); - the mean value of the sample (mean); - standard deviation (sig); - level of confidence (conf). In your answer, specify the length of the resulting confidence interval (the difference between the right and left ends), rounded to integers.

def confidence_interval(n, mean, sig, conf):
    sig = sig / (n ** (1/2))
    left = round(mean - sig * norm.ppf((1+conf)/2))
    right = round(mean + sig * norm.ppf((1+conf)/2))
    return right - left