It actually means self.Connection is equal to None, and that’s why it doesn’t like that. You have to look before that line in your code to see how it can be None instead of a Connection instance.
maybe you wanna have a look at this -> https://discourse.panda3d.org/viewtopic.php?t=4881
its pretty clean and lean thus easier to understand.
I included the culprit line up above. 
For some reason ‘self.cManager.openTCPClientConnection(IP, PORT,1000)’ is returning ‘None’.
Now that is a failed connection is it not?
Or is it an issue with the usage of that function/method?
L:lol:L
Now that I have been able to look at that other network code in detail I actually find this sample easier to understand.
It all seems to make sense to me. 
Just not sure why it wont work. lol.
EDIT: Ahhhhh took a look inside his Client.py code and found that it is just this same code bundled differently (in essence).
Interestingly when he uses the EXACT same lines in Client() it works.
But in this example it does not.
Still cannot work out why as there is almost no difference. 
Hi. You took a look into what client py?
If I need to fix stuff, I prolly will. Actually I need some help because that code is oldish. but once I know what I have to fix, I will do my best to DO so. 
I don’t program to that extent I am used to, so I am out of training. - and my time doesn’t allow me to work back into the code. Sorry, I hope you understand… 
Regards, Bigfoot29