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- (Added) Module ``interpreter`` provides a ``log_trace`` function that takes an interpreter instance and returns
a (dynamic) list of executed macro steps.
- (Added) Module ``testing`` exposes an ``ExecutionWatcher`` class that can be used to check statechart properties
with tester statecharts at runtime.
- (Changed) ``Interpreter.__init__`` does not anymore stabilize the statechart. Stabilization is done during the
first call of ``execute_once``.
- (Changed) ``Story.tell`` returns a list of ``MacroStep`` (the *trace*) instead of an ``Interpreter`` instance.
- (Changed) The name of some attributes of an event in a tester story changes (e.g. *event* becomes *consumed_event*,
*state* becomes *entered_state* or *exited_state* or *source_state* or *target_state*).
- (Removed) ``Interpreter.trace``, as it can be easily obtained from ``execute_once`` or using ``log_trace``.
- (Removed) ``Interpreter.__init__`` does not accept an ``initial_time`` parameter.
- (Fixed) Parallel state without children does not any more result into an infinite loop.