ZQLW6BX54QFHXQHJTOQ7KW3TBNE6VZZGTD3FPUOLVULYRS66NGLQC decEquiv (Some a) (Some b) with (decEquiv a b)decEquiv (Some a) (Some b) | (Yes prf) = Yes $ BothSame prfdecEquiv (Some a) (Some b) | (No ctra) = No $ fromNotEquiv ctra
decEquiv (Some a) (Some b) = case (decEquiv a b) of(Yes prf) => Yes $ BothSame prf(No ctra) => No $ fromNotEquiv ctra