fix python unittests
fix python unittests

maxvogel/NetworKit-mirror2,fmaschler/networkit,fmaschler/networkit,maxvogel/NetworKit-mirror2,fmaschler/networkit,fmaschler/networkit,fmaschler/networkit,maxvogel/NetworKit-mirror2,maxvogel/NetworKit-mirror2,fmaschler/networkit,maxvogel/NetworKit-mirror2