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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, key, part='re', scale='log', steps=50, legend=True, plotargs={}):
 """Plot the RG evolution of parameter `key`. Parameters: - part, scale, steps: see `plotdata` - legend: boolean, show the legend (default: True) - plotargs: dictionary of arguments to be passed to plt.plot """

        try:
            import matplotlib.pyplot as plt
        except ImportError:
            raise ImportError("Please install matplotlib if you want to use the plot method")
        pdat = self.plotdata(key, part=part, scale=scale, steps=steps)
        plt.plot(*pdat, label=key, **plotargs)
        if scale == 'log':
            plt.xscale('log')
        if legend:
            plt.legend()