[Python] Find the sum of the residuals

I am doing a hands on exercise of Poissons Regression of Stats with Python in Fresco Play. Problem statement is like: Load the R dataset Insurance from the MASS package. Capture the data as a pandas dataframe. Build a Poisson regression model with a log of an independent variable Holders, and dependent variable Claims. Fit the model with data, and find the sum of the residuals.

I am stuck with the last line i.e. Sum of Residuals

I used np.sum(model.resid). But answer is not accepted

Here is my code

import statsmodels.api as sm
import statsmodels.formula.api as smf
import numpy as np

INS_data = sm.datasets.get_rdataset('Insurance','MASS').data
model = smf.poisson('Claims ~ np.log(Holders)', INS_data).fit()
print(np.sum(model.resid))

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