NameError                                 Traceback (most recent call last)
/home/jscandal/sw/matplotlib/matplotlib/lib/matplotlib/backends/backend_qt4.py
in
keyReleaseEvent(self=<matplotlib.backends.backend_qt4agg.FigureCanvasQTAgg
object>, event=<PyQt4.QtGui.QKeyEvent object>)
    308 
    309     def keyReleaseEvent(self, event):
--> 310         key = self._get_key(event)
        key = undefined
        self._get_key = <bound method FigureCanvasQTAgg._get_key of
<matplotlib.backends.backend_qt4agg.FigureCanvasQTAgg object at 0x7f0393412948>>
        event = <PyQt4.QtGui.QKeyEvent object at 0x7f0393507a68>
    311         if key is None:
    312             return

/home/jscandal/sw/matplotlib/matplotlib/lib/matplotlib/backends/backend_qt4.py
in _get_key(self=<matplotlib.backends.backend_qt4agg.FigureCanvasQTAgg
object>, event=<PyQt4.QtGui.QKeyEvent object>)
    363                 return None
    364 
--> 365             key = unichr(event_key)
        key = undefined
        global unichr = undefined
        global event_key = undefined
    366             # qt delivers capitalized letters.  fix capitalization
    367             # note that capslock is ignored

NameError: name 'unichr' is not defined