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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_freq(self, x, y, title='', ylabel=None, scale='semilogy'):
 """Plot mean frequency spectrum and display in dialog. Parameters x : list vector with frequencies y : ndarray vector with amplitudes title : str plot title ylabel : str plot y label scale : str semilogy, loglog or linear """

        freq = self.frequency
        scaling = freq['scaling'].get_value()

        if ylabel is None:
            if freq['complex'].get_value():
                ylabel = 'Amplitude (uV)'
            elif 'power' == scaling:
                ylabel = 'Power spectral density (uV ** 2 / Hz)'
            elif 'energy' == scaling:
                ylabel = 'Energy spectral density (uV ** 2)'

        self.parent.plot_dialog = PlotDialog(self.parent)
        self.parent.plot_dialog.canvas.plot(x, y, title, ylabel, scale=scale)
        self.parent.show_plot_dialog()