The next code includes the code based on the estimation of sample size n using a Margin of error equal to 4000.  The concept and code related to computing sample size n employs the discussion made in Track 07 - section 2.10.

from scipy.stats import norm

p = 0.90      # Confidence level: population percentage covered by the interval

muz = 0       # mean of the standard normal

sigmaz = 1    # standard deviation of standard normal

alfa = 1-p    # obtaining the significance level: alpha

pr = 1-alfa/2 # percentage of the population higher than the critical level z

z = norm.ppf(pr, muz, sigmaz) # computing the critical z alpha/2

s = std_sample  # compute the standard deviation of the sample

# Range of the confidence interval

W = 4000

# Finally the final sample size n.

n = round((2*z*s/W)**2,0)

n = int(n)

print('Sample size = ',n)

Sample size = 100