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.

from math import sqrt

def conf_interval(n, mean, sig, conf):
    z_value = abs(conf - mean)
    sq_n = sqrt(n)
    interval = z_value / sq_n
    return interval

conf_interval(3, 1, 2, 1)