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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 set_fig_size(self, width, height=None):
 """Set the figure size in inches. Sets the figure size with a call to fig.set_size_inches. Default in code is 8 inches for each. Args: width (float):
 Dimensions for figure width in inches. height (float, optional):
 Dimensions for figure height in inches. Default is None. """

        self.figure.figure_width = width
        self.figure.figure_height = height
        return