Tezos_raw_protocol_011_PtHangz2.Vote_reprtype proposal = Tezos_protocol_environment_011_PtHangz2.Protocol_hash.ta protocol change proposal
votes can be for, against or neutral. Neutral serves to count towards a quorum
val ballot_encoding :
ballot Tezos_protocol_environment_011_PtHangz2.Data_encoding.t