Set headers to None to exclude specific default headers

[GeekDuanLian]

Just like requests

s = Session(headers={'authorization': 'xxx'})

But you want to visit an external website, the authorization cannot be leaked

s.get('xxx', headers={'authorization': None})

This way to exclude the default headers

[tomchristie]

I'm not convinced if we'd want to support this usage or not.
Having a special casing behaviour for None in this way seems a bit brittle.

(?)

[GeekDuanLian]

Are there other ways to exclude default headers?
At least it should have this function, and requests do this.