docs: def export(self, title, data):
          """Generate graph from the data.
  
          Example for the mem plugin:
          {'percent': [
              (datetime.datetime(2018, 3, 24, 16, 27, 47, 282070), 51.8),
              (datetime.datetime(2018, 3, 24, 16, 27, 47, 540999), 51.9),
              (datetime.datetime(2018, 3, 24, 16, 27, 50, 653390), 52.0),
              (datetime.datetime(2018, 3, 24, 16, 27, 53, 749702), 52.0),
              (datetime.datetime(2018, 3, 24, 16, 27, 56, 825660), 52.0),
              ...
              ]
          }
  
          Return:
          * True if the graph have been generated
          * False if the graph have not been generated
          """
          if data == {}:
              return False
  
          chart = DateTimeLine(title=title.capitalize(),
                               width=self.width,
                               height=self.height,
                               style=self.style,
                               show_dots=False,
                               legend_at_bottom=True,
                               x_label_rotation=20,
                               x_value_formatter=lambda dt: dt.strftime('%Y/%m/%d %H:%M:%S'))
          for k, v in iteritems(time_serie_subsample(data, self.width)):
              chart.add(k, v)
          chart.render_to_file(os.path.join(self.path,
                                            title + '.svg'))
          return True