code: def add_labelset(self, labelset):
          
          if not isinstance(labelset, PlotLabelset):
              self.log_exc(u"labelset must be an instance of PlotLabelset", None, True, TypeError)
          self.labelsets.append(labelset)
          self.log(u"Added labelset")
docs: Add a set of labels to the plot.
  
          :param labelset: the set of labels to be added
          :type  labelset: :class:`~aeneas.plotter.PlotLabelset`
          :raises: TypeError: if ``labelset`` is not an instance of :class:`~aeneas.plotter.PlotLabelset`