Fix declaration of arity, to make Opt produce correct number of values in both success and failure cases
Fix declaration of arity, to make Opt produce correct number of values in both success and failure cases

cdglabs/ohm,anfedorov/ohm,harc/ohm,coopsource/ohm,cdglabs/ohm,harc/ohm,anfedorov/ohm,DanielTomlinson/ohm,anfedorov/ohm,harc/ohm,coopsource/ohm,cdglabs/ohm,DanielTomlinson/ohm,DanielTomlinson/ohm,coopsource/ohm