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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_container_mapping(self):
 """Returns a mapping of container -> postition """

        layout = self.context.getLayout()
        container_mapping = {}
        for slot in layout:
            if slot["type"] != "a":
                continue
            position = slot["position"]
            container_uid = slot["container_uid"]
            container_mapping[container_uid] = position
        return container_mapping