How to have a fully connected graph nodes in Python

See more:

Python

Python2.7

Hi I need to write a method for having fully connected graph nodes with weighted. I was wondering is there any library which I can used in this manner and how can write this.
would you please give me an example.Thank you

List_Nodes=[A,B,C]
List_Weight=[20,30,20,10,30,15]
A--B weight:20
A--C  weight:30
B--A  weight:20
B--C  weight:10
C--A  weight:30
C--B  weight:15

Regards,
Negar

What I have tried:

import itertools
#I see someone use itertools but I'm not sure how I can used it