'Add a DataSeries to the subplot.
:param label: A name for the DataSeries values.
:type label: string.
:param dataSeries: The DataSeries to add.
:type dataSeries: :class:`pyalgotrade.dataseries.DataSeries`.'

def addDataSeries(self, label, dataSeries, defaultClass=LineMarker):

    callback = (lambda bars: get_last_value(dataSeries))
    self.__callbacks[callback] = self.getSeries(label, defaultClass)
