Hi @mikemanger - thank you enormously for the excellent changes here in this pull request - we really appreciate your work here. I am eager to get this PR moving ahead.

I had a few things which I wanted to go over with you to get us to that stage. With all this, please keep in mind I am not an experienced Python developer and so there might be some things I am off the mark about and I'm happy to learn and be corrected along the way.

These were the items I had in mind:

• Earlier today, I merged in your work from #84 which have some changes in common with this PR - namely changing assertEquals to assertEqual. This is now in master and in the latest version of the package (8.0.2) and hopefully bringing those changes across in to this PR will reduce the number of changes.
• I am not too familiar with the github workflow side of things but I am happy to go ahead with those changes for the automated testing side of things.
• I ran tox and that was showing some issues with version Python 3.7, namely this issue shown below. Python version 3.6 is skipped and 3.7 doesn't run properly:
  

The error for Python 7 I was seeing on my machine was this:

How would we feel about removing Python versions 3.6 and 3.7 from tests.yml and tox.ini? I have left these as things to consider below. I'm happy to update the documentation saying that we do not support those two versions any more. Having said that, I did test with Python 3.6 and the wrapper appears to still be working as before.

• From Python version 3.11 and onwards, I noticed this deprecation warning that came up:

\createsend-python\lib\createsend\utils.py:106: DeprecationWarning: ssl.SSLContext() without protocol argument is deprecated.
    context = ssl.SSLContext()

\createsend-python\lib\createsend\utils.py:106: DeprecationWarning: ssl.PROTOCOL_TLS is deprecated
    context = ssl.SSLContext()

I attempted to remove this warning by changing utils.py line 106:

From:
ssl.SSLContext()

To:
ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)

But that resulted in this failure:

FAILED test/test_verifiedhttpsconnection.py::VerifiedHTTPSConnectionTestCase::test_verified_connection - ValueError: check_hostname requires server_hostname

For now, I was thinking we're happy to leave it as a warning and figure out a fix for that separately.

So with all that in mind after:

• this PR has the latest from master merged in; and
• if you agree that removing 3.6 and 3.7 is a good idea and we do so

I'm happy to get this approved, merged and released ASAP. Thank you once again for your help and pushing for this code base to be modernised.

LGTM - Thank you @mikemanger - really appreciate the changes, I will go about getting these in and releasing them in a next version ASAP.

I tested out tox, unit tests and ran then the wrapper code. All working as expected.