Initialise beam with bunch list

I'm wondering what the correct way is to initialise a beam with a list of bunches? I did it by using the bunch_list keyword in Beam.__init__ but when I tried to track the beam I got errors because there are also steps in Beam.init_beam that are required. update_filling_pattern and update_distance_between_bunches are easy to call yourself but there is also all the setup of the MPI.

Is there already a way to do those steps without calling init_beam since that overwrites the bunch list?