s = pd.Series([52])
    >>> _stata_elapsed_date_to_datetime_vec(dates , "%tw")
    0   1961-01-01
    dtype: datetime64[ns]

    Notes
    -----
    datetime/c - tc
        milliseconds since 01jan1960 00:00:00.000, assuming 86,400 s/day
    datetime/C - tC - NOT IMPLEMENTED
        milliseconds since 01jan1960 00:00:00.000, adjusted for leap seconds
    date - td
        days since 01jan1960 (01jan1960 = 0)
    weekly date - tw
        weeks since 1960w1
        This assumes 52 weeks in a year, then adds 7 * remainder of the weeks.
        The datetime value is the start of the week in terms of days in the
        year, not ISO calendar weeks.
    monthly date - tm
        months since 1960m1
    quarterly date - tq
        quarters since 1960q1
    half-yearly date - th
        half-years since 1960h1 yearly
    date - ty
        years since 0000
    r?