Syntax error at Space Bar plugin

Hi, Yanone’s Space Bar plugin does not work.
There is no changed when I execute it from the view menu. The macro panel displays the following error.

Traceback (most recent call last):
File “/Users/JOON/Library/Application Support/Glyphs/Plugins/Space Bar.glyphsReporter/Contents/Resources/spacinginvaderlib/init.py”, line 1273, in foreground
instanceMasters = [x[0] for x in font.instances[0].sortedInterpolationValues]
File “/Users/JOON/Library/Application Support/Glyphs/Plugins/Space Bar.glyphsReporter/Contents/Resources/spacinginvaderlib/init.py”, line 195, in
GSInstance.sortedInterpolationValues = property(lambda self: GSInstance_SortedInterpolationValues(self))
File “/Users/JOON/Library/Application Support/Glyphs/Plugins/Space Bar.glyphsReporter/Contents/Resources/spacinginvaderlib/init.py”, line 191, in GSInstance_SortedInterpolationValues
instanceMastersKeys.sort(key=lambda x: self.font().masters.index(self.font().masters))
File “/Users/JOON/Library/Application Support/Glyphs/Plugins/Space Bar.glyphsReporter/Contents/Resources/spacinginvaderlib/init.py”, line 191, in
instanceMastersKeys.sort(key=lambda x: self.font().masters.index(self.font().masters))
TypeError: ‘NSKVONotifying_GSFont’ object is not callable