Context.Dalval shards :
t ->
?level:Tezos_protocol_alpha.Protocol.Alpha_context.Raw_level.t ->
?delegates:Signature.public_key_hash list ->
unit ->
Tezos_protocol_plugin_alpha.Plugin.RPC.Dal.S.shards_output
Tezos_base.TzPervasives.tzresult
Lwt.t