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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 add_image(self, filename, *, width=NoEscape(r'0.8\textwidth'), placement=NoEscape(r'\centering')):
 """Add an image to the figure. Args ---- filename: str Filename of the image. width: str The width of the image placement: str Placement of the figure, `None` is also accepted. """


        if width is not None:
            if self.escape:
                width = escape_latex(width)

            width = 'width=' + str(width)

        if placement is not None:
            self.append(placement)

        self.append(StandAloneGraphic(image_options=width,
                                      filename=fix_filename(filename)))