{{alias}}( λ )
    Returns the expected value of an exponential distribution.

    If provided `NaN` as any argument, the function returns `NaN`.

    If provided a negative value for `λ`, the function returns `NaN`.

    Parameters
    ----------
    λ: number
        Rate parameter.

    Returns
    -------
    out: number
        Expected value.

    Examples
    --------
    > var v = {{alias}}( 11.0 )
    ~0.091
    > v = {{alias}}( 4.5 )
    ~0.222

    See Also
    --------