Possible logic error in `getScriptLanguageSystems`

[cmyr]

On the following line in this function, the sc value may be None, but this case does not appear to be handled, which means that the returned map could contain an unexpected None value.

The called function currently returns None if the tag is DFLT, which we skip earlier in this function so this is probably fine? but future changes might break this, and it might make sense to check this value before inserting it in the map.

ufo2ft/Lib/ufo2ft/featureWriters/ast.py

Line 38 in cea60d7

sc = unicodedata.ot_tag_to_script(script)