
{{alias}}( λ )
    Returns the excess kurtosis of a Planck distribution with shape parameter
    `λ`.

    If `λ <= 0`, the function returns `NaN`.

    Parameters
    ----------
    λ: number
        Shape parameter.

    Returns
    -------
    out: number
        Excess kurtosis.

    Examples
    --------
    > var v = {{alias}}( 0.1 )
    ~6.0100
    > v = {{alias}}( 1.5 )
    ~8.7048

    See Also
    --------

