{{alias}}()
    Returns an accumulator function which incrementally computes a sum.

    If provided a value, the accumulator function returns an updated sum. If not
    provided a value, the accumulator function returns the current sum.

    If provided `NaN` or a value which, when used in computations, results in
    `NaN`, the accumulated value is `NaN` for all future invocations.

    For long running accumulations or accumulations of large numbers, care
    should be taken to prevent overflow.

    Returns
    -------
    acc: Function
        Accumulator function.

    Examples
    --------
    > var accumulator = {{alias}}();
    > var s = accumulator()
    null
    > s = accumulator( 2.0 )
    2.0
    > s = accumulator( -5.0 )
    -3.0
    > s = accumulator()
    -3.0

    See Also
    --------