def METHOD_NAME(x, ps):
    """
    Evaluate polynomial `lambda_n(x)` given a tuple of parameters `ps` with length
    equal to the polynomial degree.
    Parameters
    -----------
    x : :class:`numpy.ndarray`
        X values to calculate the function at.
    ps: :class:`tuple`
        Parameter set tuple. E.g. parameters `(a, b)` from :math:`f(x) = (x-a)(x-b)`.
    Returns
    --------
    :class:`numpy.ndarray`
    """
    if not isinstance(x, np.ndarray):
        x = np.array(x)
    result = np.ones(len(x))
    for p in ps:
        result = result * (x - p)
    return result.astype(float)