if not add_noise:
>               assert_almost_equal(np.dot(s1_, s1) / n_samples, 1, decimal=2)
E               AssertionError: 
E               Arrays are not almost equal to 2 decimals
E                ACTUAL: 0.99488635116165225
E                DESIRED: 1

X          = array([[ 0.13588498, -0.99782607],
       [-0.10332272,  0.9968851 ],
       [-0.14849044,  0.98682719],
       ..., 
       [ 0.12009723, -1.00134168],
       [ 0.1686379 , -0.99053268],
       [ 0.13543362, -0.99792658]])