delphyne-crash : TypeError

[stonier]

Running simulation indefinitely.
Collisions have been detected!

racer2 and racer3 have crashed at [-0.04885  0.88715  1.3957 ]!
--> racer2 was going at 5.0 m/s and hit racer3.
Simulation ended. I'm happy, you should be too.
= Simulation stats ==========================
  Simulation runs: 434
  Simulation steps: 936
  Elapsed simulation time: 9.359999999999845s
  Elapsed real time: 9.564274264026608s
=============================================
Traceback (most recent call last):
  File "/mnt/mervin/workspaces/devel/maliput/install/delphyne-demos/bin/delphyne-crash", line 9, in <module>
    delphyne_demos.demos.crash.main()
  File "/mnt/mervin/workspaces/devel/maliput/install/delphyne-demos/lib/python3.6/site-packages/delphyne_demos/demos/crash.py", line 137, in main
    simulation_tree.tick_tock(period=tree_time_step)
  File "/mnt/mervin/workspaces/devel/maliput/install/delphyne/lib/python3.6/site-packages/delphyne/trees.py", line 75, in tick_tock
    self.tick(pre_tick_handler, post_tick_handler)
  File "/opt/ros/dashing/lib/python3.6/site-packages/py_trees/trees.py", line 320, in tick
    handler(self)
  File "/mnt/mervin/workspaces/devel/maliput/install/delphyne-demos/lib/python3.6/site-packages/delphyne_demos/demos/crash.py", line 59, in check_for_agent_collisions
    agent1_pose = agent1.get_pose()
TypeError: Unable to convert function return value to a Python type! The signature was
        (self: delphyne.agents.Agent) -> Eigen::Transform<double, 3, 1, 0>