This script will work if you are viewing “All Glyphs”. What it’s supposed to do is copy the A glyph into the Z slot. But if you display only the UC characters, then run it:
import robofab.world
f = robofab.world.CurrentFont()
g = f["A"]
f.removeGlyph("Z")
f.insertGlyph(g, "Z")
f.update()
Instead what you get is an error:
File “lib/fontObjects/robofabWrapper.pyc”, line 2447, in insertGlyph
File “/Applications/RoboFont.app/Contents/Resources/lib/python2.7/defconAppKit/controls/glyphCollectionView.py”, line 485, in insert
File “/Applications/RoboFont.app/Contents/Resources/lib/python2.7/vanilla/vanillaList.py”, line 900, in insert
IndexError: NSRangeException – Index 263 out of bounds of [0…24]