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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 get_slot_position_for(self, instance):
 """Returns the slot where the instance passed in is located. If not found, returns None """

        uid = api.get_uid(instance)
        slot = filter(lambda s: s['analysis_uid'] == uid, self.getLayout())
        if not slot:
            return None
        return to_int(slot[0]['position'])