Python diamond inheritance problem for IVectorSegment

In the IVectorSegment class, there is a diamond inheritance problem,

For now, the solution used to solve this issue is hard-coded. We have to solve this issue in a more elegant way. After a dicussion with @amohammadi, he pointed me to the method super in python. A good illustration of this method is in: http://stackoverflow.com/questions/222877/what-does-super-do-in-python