L2Reg error or misleading docs about sigpy HOT 3 OPEN

import numpy as np
from sigpy.prox import L2Reg
import unittest

def g_in(r_in_minus, gamma_in_minus):
    eta_in_plus = (1 + gamma_in_minus)
    xhat_in_plus = r_in_minus * gamma_in_minus / eta_in_plus
    return xhat_in_plus, eta_in_plus

class TestingDenoisers(unittest.TestCase):

    def test_g_in(self):
        N=10
        operator = L2Reg((N,1), 1.)
        r = np.random.randn(N,1)
        gamma = abs(np.random.randn())
        xhat, eta = g_in(r, gamma)
        C = np.cov(r, xhat, rowvar=False)
        eta_check = gamma/(C[1,0]/C[0,0])
        self.assertAlmostEqual(eta_check, eta)
        self.assertAlmostEqual(np.linalg.norm(xhat-operator(1/gamma, r)),0.)

if __name__ == '__main__':
    unittest.main()