def METHOD_NAME():
    """
    Check if `from_samples()` raises an exception when the expected
    similarity score between to random symbols is positive.
    """
    alph = seq.ProteinSequence.alphabet
    matrix = align.SubstitutionMatrix(
        alph, alph, np.ones((len(alph), len(alph)), dtype=int)
    )
    # Uniform background frequencies
    freq = np.ones(len(alph))
    with pytest.raises(ValueError):
        estimator = EValueEstimator.from_samples(alph, matrix, -10, freq