fix: UnboundLocalError

[OmLanke]

Summary

Fixes the UnboundLocalError being raised for the br_cmd variable at line 133.

Information

• This PR fixes an issue.
• This PR adds something new (e.g. new method or parameters).
• This PR is a breaking change (e.g. methods or parameters removed/renamed).
• This PR is not a code change (e.g. documentation, README, typehinting,
  examples, ...).

Checklist

• I have searched the open pull requests for duplicates.
• If code changes were made then they have been tested.
  • I have updated the documentation to reflect the changes.
• If type: ignore comments were used, a comment is also left explaining why.

[BobDotCom]

Can you provide an example of some code that causes this error?

[OmLanke]

Can you provide an example of some code that causes this error?

I myself did not encounter this issue in my limited testing, but users have reported the error, and this change fixes it.

This also fixes a major oversight where br_cmd will not be defined at line 139.