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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 check_label(self):
 """ Check label for target and fix if necessary. Forcing the target name to Saturn here, because some observations of the rings have moons as a target, but then the standard map projection onto the Saturn ring plane fails. See also -------- https://isis.astrogeology.usgs.gov/IsisSupport/index.php/topic,3922.0.html """

        if not self.is_ring_data:
            return
        targetname = getkey(
            from_=self.pm.raw_cub, grp="instrument", keyword="targetname"
        )

        if targetname.lower() != "saturn":
            editlab(
                from_=self.pm.raw_cub,
                options="modkey",
                keyword="TargetName",
                value="Saturn",
                grpname="Instrument",
            )