def METHOD_NAME(ddof):
    X = np.random.random((100, 5))
    X1 = X[: len(X) // 2]
    X2 = X[len(X) // 2 :]
    C1 = covariance.EmpiricalCovariance(ddof=ddof)
    for x, _ in stream.iter_array(X1):
        C1.update(x)
    C2 = covariance.EmpiricalCovariance(ddof=ddof)
    for x, _ in stream.iter_array(X):
        C2.update(x)
    for x, _ in stream.iter_array(X2):
        C2.revert(x)
    for k in C1._cov:
        assert math.isclose(C1._cov[k].get(), C2._cov[k].get())