def add_data(self, data):
super(Plot, self).add_data(data)<EOL>
Add data to the plot::

        # A data set with 1 point: ("12:30", 2)
        d1 = ["12:30", 2]

        # A data set with 2 points: ("01:00", 2) and
        #                           ("14:20", 6)
        d2 = ["01:00", 2, "14:20", 6]

        graph.add_data(
                data = d1,
                title = 'One',
        )
        graph.add_data(
                data = d2,
                title = 'Two',
        )

Note that the data must be in (time, value) pairs, and
the date format
may be any date that is parseable by dateutil.