code: def get_container_mapping(self):
          
          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
docs: Returns a mapping of container -> postition