Transition Model Type "" behaves differently from "deterministic"

[sebimarkgraf]

Hi,

I am just raising this issue for others, that will potentially trip over this small detail.
When choosing "" or "deterministic", while this creates the same object type of transition model,
the loss implementation in the bisim agent behaves different:

deep_bisim4control/agent/bisim_agent.py

Line 229 in 5967b6d

if self.transition_model_type == '':

This could potentially be fixed by choosing to check for "deterministic" and changing the default to "deterministic" instead of the empty string.