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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 show_label(self, text, size = None, color = None, font_desc = None):
 """display text. unless font_desc is provided, will use system's default font"""

        font_desc = pango.FontDescription(font_desc or _font_desc)
        if color: self.set_color(color)
        if size: font_desc.set_absolute_size(size * pango.SCALE)
        self.show_layout(text, font_desc)