ys:

        >>> ts.first('3D')
                    A
        2018-04-09  1
        2018-04-11  2

        Notice the data for 3 first calendar days were returned, not the first
        3 days observed in the dataset, and therefore data for 2018-04-13 was
        not returned.
        zqfirst is deprecated and will be removed in a future version. Please create a mask and filter using `.loc` insteadṛ