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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_optional_elements(self):
 """Sets elements considered option by RSS spec"""

        self.set_categories()
        self.set_copyright()
        self.set_generator()
        self.set_image()
        self.set_language()
        self.set_last_build_date()
        self.set_managing_editor()
        self.set_published_date()
        self.set_pubsubhubbub()
        self.set_ttl()
        self.set_web_master()