{{alias}}( [month[, year]] )
    Returns the number of days in a month.

    By default, the function returns the number of days in the current month
    of the current year (according to local time). To determine the number of
    days for a particular month and year, provide `month` and `year` arguments.

    A `month` may be either a month's integer value, three letter abbreviation,
    or full name (case insensitive).

    The function's return value is a generalization and does **not** take into
    account inaccuracies due to daylight savings conventions, crossing
    timezones, or other complications with time and dates.

    Parameters
    ----------
    month: string|integer|Date (optional)
        Month (or `Date`).

    year: integer (optional)
        Year.

    Returns
    -------
    out: integer
        Days in a month.

    Examples
    --------
    > var num = {{alias}}()
    <number>
    > num = {{alias}}( 2 )
    <number>
    > num = {{alias}}( 2, 2016 )
    29
    > num = {{alias}}( 2, 2017 )
    28

    // Other ways to supply month:
    > num = {{alias}}( 'feb', 2016 )
    29
    > num = {{alias}}( 'february', 2016 )
    29

    See Also
    --------