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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def to_dot(self):
 """Produces a ball and stick graph of this state machine. Returns ------- `graphviz.Digraph` A ball and stick visualization of this state machine. """

        from graphviz import Digraph
        dot = Digraph(format='png')
        for state in self.states:
            if isinstance(state, TransientState):
                dot.node(state.state_id, style='dashed')
            else:
                dot.node(state.state_id)
            for transition in state.transition_set:
                dot.edge(state.state_id, transition.output.state_id, transition.label())
        return dot