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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 plot_stateseries( self, names: Optional[Iterable[str]] = None, average: bool = False, **kwargs: Any) \ -> None: """Plot the `state` series of the handled model. See the documentation on method |Element.plot_inputseries| for additional information. """

        self.__plot(self.model.sequences.states, names, average, kwargs)