BUG: key error in plot time series

KeyError: '2012' occuring on PlotTimeSeries.

Check plot method

added bug refactoring labels

mentioned in commit 91feab0c

added .done label

added merged in Develop label and removed .done label

mentioned in issue #171 (closed)

mentioned in merge request !145 (merged)

closed with commit 91feab0c

closed with merge request !145 (merged)

mentioned in commit c1cb2c8e