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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 base_style(self):
 """ Sibling CT_Style element this style is based on or |None| if no base style or base style not found. """

        basedOn = self.basedOn
        if basedOn is None:
            return None
        styles = self.getparent()
        base_style = styles.get_by_id(basedOn.val)
        if base_style is None:
            return None
        return base_style