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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(self, freq=None, figsize=(15, 5), title=None, logy=False, **kwargs):
 """ Helper function for plotting the series. Args: * freq (str):
 Data frequency used for display purposes. Refer to pandas docs for valid freq strings. * figsize ((x,y)):
 figure size * title (str):
 Title if default not appropriate * logy (bool):
 log-scale for y axis * kwargs: passed to pandas' plot method """


        if title is None:
            title = self._get_default_plot_title(
                freq, 'Equity Progression')

        ser = self._get_series(freq).rebase()
        return ser.plot(figsize=figsize, logy=logy,
                        title=title, **kwargs)