Plotter: using permute and pivot together does not work

[mdigiorgio]

When trying to plot two or more traces with pivoting and permute python raises an exception. In my example I want to pivot on a column having 2 different values, and want to permute on 2 columns. Hence, I should get 4 subplots, but I get the following exception:

~/lisa/libs/trappy/trappy/plotter/PlotLayout.py in get_axis(self, plot_index)
    144             return self._attr["axes"]
    145         else:
--> 146             return self._attr["axes"][self.get_2d(plot_index)]
    147 
    148     def get_fig(self):

IndexError: index 2 is out of bounds for axis 0 with size 2