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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 descriptionHtml(self):
 """ HTML help describing the class. For use in the detail editor. """

        if self.cls is None:
            return None
        elif hasattr(self.cls, 'descriptionHtml'):
            return self.cls.descriptionHtml()
        else:
            return ''