For reference, this commit is the change in urllib3 to not add a duplicate header if set before: https://github.com/urllib3/urllib3/commit/eb28aec79de922100b246f2ac1cd4625394ff70c
For reference, this commit is the change in urllib3 to not add a duplicate header if set before: https:/ /github. com/urllib3/ urllib3/ commit/ eb28aec79de9221 00b246f2ac1cd46 25394ff70c