code: async def start_async(self):
          
          if self.run_task:
              raise Exception("A PartitionManager cannot be started multiple times.")
  
          partition_count = await self.initialize_stores_async()
          _logger.info("%r PartitionCount: %r", self.host.guid, partition_count)
          self.run_task = asyncio.ensure_future(self.run_async())
docs: Intializes the partition checkpoint and lease store and then calls run async.