prefixes doesn't work in .py?

[minikui]

when I write
filename = ''
in .py, I just want the file path will appear in quotes, so I can select to autocomplete.
So I add these codes in config.cson, but nothing happen

prefixes: [
      "\\w+\\s+=\\s+['\"]"
    ]

Is the prefixes wrong? Or something else...
Thanks