Trigger next agent to :py:meth:`~creamas.core.CreativeAgent.act` in
        the current step.

def next(self):
        """Trigger next agent to :py:meth:`~creamas.core.CreativeAgent.act` in
        the current step.
        """
        # all agents acted, init next step
        t = time.time()
        if len(self._agents_to_act) == 0:
            self._init_step()

        addr = self._agents_to_act.pop(0)
        aiomas.run(until=self.env.trigger_act(addr=addr))
        t2 = time.time()
        self._step_processing_time += t2 - t

        # all agents acted, finalize current step
        if len(self._agents_to_act) == 0:
            self._finalize_step()