{{alias}}()
    Returns an accumulator function which incrementally computes a mid-range.

    The mid-range is the arithmetic mean of maximum and minimum values.
    Accordingly, the mid-range is the midpoint of the range and a measure of
    central tendency.

    If provided a value, the accumulator function returns an updated mid-range.
    If not provided a value, the accumulator function returns the current mid-
    range.

    If provided `NaN`, the mid-range is `NaN` for all future invocations.

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

    Examples
    --------
    > var accumulator = {{alias}}();
    > var v = accumulator()
    null
    > v = accumulator( 3.14 )
    3.14
    > v = accumulator( -5.0 )
    ~-0.93
    > v = accumulator( 10.1 )
    2.55
    > v = accumulator()
    2.55

    See Also
    --------