Seems like you have SocketServer.py
somewhere in python path.
Check using following command:
python -c "import SocketServer; print(SocketServer.__file__)"
Renaming that file will solve your problem.
UPDATE
Rename the file /Users/ddl449/Projects/visualization/SocketServer.py
. If there is /Users/ddl449/Projects/visualization/SocketServer.pyc
, remove that file .