Wow thanks a lot for such a fast fix!
That is a lifesaver function for glyph proofing

I am having problems with a drawBot script to proof all glyphs in a variable font.

I am adding all glyphs from the list generated by listFontGlyphNames() to a FormattedString with appendGlyph, but it stops working whenever I set any value to fontVariations. (Exactly the same behavior reported here https://github.com/typemytype/drawbot/issues/402, so I discarded any problems with the font I'm using)

I was wondering if there are any workarounds to this problem or if this is still impossible at this time.

Here's the code I'm using:

pageSize = 'A4'

fPath = '/Users/renan/Desktop/ABCDiatypePlusVariable.ttf'

border = 20

class fontInstance:
    def __init__(self, name, axisValues):
        self.axisValues = axisValues
        self.name = name

instanceList = listNamedInstances(fPath)
instances = []

for i in instanceList:
    instanceName = i
    axisValues = instanceList[i]
    instance = fontInstance(instanceName, axisValues)
    instances.append(instance)

txt = FormattedString()
txt.font(fPath)
txt.fontSize(20)

glyphNameList = txt.listFontGlyphNames()

for g in glyphNameList:
    for i in instances:
        txt.fontVariations(**i.axisValues)
        txt.appendGlyph(g)
    txt.append('\n')

while txt:
    newPage(pageSize)
    txt = textBox(txt, (border, border, width() - border*2, height() - border*2))