Comment 1 for bug 1888373

Adding a break point just before the failing point reported in the snippet, this is the MRO of the objects, depending on the version:

py38:
(<class 'eventlet.green.ssl.GreenSSLSocket'>, <class 'ssl.SSLSocket'>, <class 'socket.socket'>, <class '_socket.socket'>, <class 'object'>)

py36:
(<class 'eventlet.green.ssl.GreenSSLSocket'>, <class 'ssl.SSLSocket'>, <class 'eventlet.greenio.base.GreenSocket'>, <class 'object'>)

In py36, the instance of the class GreenSSLSocket, do not inherit from socket.