Need help to write data onto an XML file after reading data from another xml file

[varun7rs at gmail.com]

I try to add an edge with the source id and destination id over a loop but this is the error I am getting. And the range for the for addEdge is something I have no clue about. 

python export.py --output topology.xml --xml germany50.xml
Traceback (most recent call last):
  File "export.py", line 239, in <module>
    main(sys.argv[1:])
  File "export.py", line 234, in main
    network.addEdge( PHY_LINKS( j , sourcen, destnn, sid, did, cap_bdw) )
  File "/home/srva/Approach_Read.py", line 89, in addEdge
    self.nodes[ edge.SourceID ].addInEdge( edge )
IndexError: list index out of range

Thank You