arbitraryEmptyTx :: Gen Tx
arbitraryEmptyTx = do
    v    <- arbitrary
    no   <- choose (1,5)
    ni   <- choose (1,5)
    outs <- vectorOf no arbitraryTxOut
    ops  <- vectorOf ni arbitraryOutPoint
    t    <- arbitrary
    s    <- arbitrary
    return $ createTx v (map (\op -> TxIn op BS.empty s) (nub ops)) outs t
arbitraryEmptyTx :: Gen Tx
arbitraryEmptyTx = do
    v    <- arbitrary
    no   <- choose (1,5)
    ni   <- choose (1,5)
    outs <- vectorOf no arbitraryTxOut
    ops  <- vectorOf ni arbitraryOutPoint
    t    <- arbitrary
    s    <- arbitrary
    return $ createTx v (map (\op -> TxIn op BS.empty s) (nub ops)) outs t
arbitraryEmptyTx = do
    v    <- arbitrary
    no   <- choose (1,5)
    ni   <- choose (1,5)
    outs <- vectorOf no arbitraryTxOut
    ops  <- vectorOf ni arbitraryOutPoint
    t    <- arbitrary
    s    <- arbitrary
    return $ createTx v (map (\op -> TxIn op BS.empty s) (nub ops)) outs t