prefixes doesn't work in .py?

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

Start by reproducing the Python case with the `prefixes` setting in `config.cson`, using the reported assignment and quoted path. Check whether the configured pattern is recognized and determine what behavior would confirm that path completion is triggered after the quote; done means the file path can be selected for autocomplete.

Written by the indexing model from the issue text.