When our python tests call a WiredTiger function that fails we print out the top level error, but it would be useful to also see the sub_level_error codes when they are available since they provide more useful context into the failure.

For example if we try to open a backup cursor when WiredTiger is in live restore mode the top level error is just

_wiredtiger.WiredTigerError: Invalid argument 

while sub_level_error details provide us the more useful

WT_CONFLICT_LIVE_RESTORE, "backup cannot be taken when live restore is enabled" 

Here's an example of printing additional details at the python layer when failing to open a backup cursor.

try:  
    backup_session = self.conn.open_session("backup:")
except wiredtiger.WiredTigerError:  
    err, sub_level_err, err_msg = self.session.get_last_error()
    self.prout(f"Error: {err}  {sub_level_err} {err_msg}") 

but ideally we can hook this logic into the SWIG interface to automatically report this on a failure.

SWIG_ERROR_IF_NOT_SET in wiredtiger.i is a a good starting point, but we need to determine how to access the session and call WT_SESSION::get_last_error() to access the sub_level_error data, along with any required NULL checking.