fontbakery: VF naming convention results in "Value is empty."

Observed behaviour

4298 ± : fontbakery check-googlefonts Karla-Italic\[wght\].ttf                                                                                                   [37m] ✖ ✹ ✭
Validation of expected values failed:
fonts: Value is empty. (value: ())
usage: fontbakery check-googlefonts [-h] [-c CHECKID] [-x EXCLUDE_CHECKID]
                                    [-v] [-l LOGLEVEL] [-m LOGLEVEL_MESSAGES]
                                    [-n] [-C] [-S] [-L] [--json JSON_FILE]
                                    [--ghmarkdown MD_FILE] [--html HTML_FILE]
                                    [-g ITERATED_ARG] [-o ORDER]
                                    [fonts [fonts ...]]

Expected behaviour

Expectation is that fontbakery will run as usual.

Resources and exact process needed to replicate

fontbakery 0.7.8 any similarly named font file should work. i.e.

foofont-italic\[wdth\].ttf
typicalsans\[wght\].ttf