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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_return(self):
 """Sets the return parameter with description and rtype if any"""

        # TODO: manage return retrieved from element code (external)
        # TODO: manage different in/out styles
        if type(self.docs['in']['return']) is list and self.dst.style['out'] not in ['groups', 'numpydoc', 'google']:
            # TODO: manage return names
            # manage not setting return if not mandatory for numpy
            lst = self.docs['in']['return']
            if lst:
                if lst[0][0] is not None:
                    self.docs['out']['return'] = "%s-> %s" % (lst[0][0], lst[0][1])
                else:
                    self.docs['out']['return'] = lst[0][1]
                self.docs['out']['rtype'] = lst[0][2]
        else:
            self.docs['out']['return'] = self.docs['in']['return']
            self.docs['out']['rtype'] = self.docs['in']['rtype']