async def prestart(self, server: protocol.Server) -> None:
    (await super().prestart(server))
    self.server_slice = cast(Server, server.get_slice(SLICE_SERVER))
    self.agentmanager = cast(AgentManager, server.get_slice(SLICE_AGENT_MANAGER))
async def prestart(self, server: protocol.Server) -> None:
    (await super().prestart(server))
    self.server_slice = cast(Server, server.get_slice(SLICE_SERVER))
    self.agentmanager = cast(AgentManager, server.get_slice(SLICE_AGENT_MANAGER))