diff --git a/Readme.md b/Readme.md
index b1ff00e..30bb259 100644
--- a/Readme.md
+++ b/Readme.md
@@ -137,11 +137,8 @@ You can now subscribe to Transfer events by calling `subscribe` on the contract
 instance.
 
 ```nim
-proc handleTransfer(transferResult: ?!Transfer) =
-  if transferResult.isOk:
-    echo "received transfer: ", transferResult.value
-  else:
-    echo "error during transfer: ", transferResult.error.msg
+proc handleTransfer(transferResult: Transfer) =
+  echo "received transfer: ", transferResult.value
 
 let subscription = await token.subscribe(Transfer, handleTransfer)
 ```
diff --git a/ethers/contracts/filters.nim b/ethers/contracts/filters.nim
index 6e6c0cf..09d2ca0 100644
--- a/ethers/contracts/filters.nim
+++ b/ethers/contracts/filters.nim
@@ -6,7 +6,7 @@ import ./contract
 import ./events
 import ./fields
 
-type EventHandler*[E: Event] = proc(event: ?!E) {.gcsafe, raises:[].}
+type EventHandler*[E: Event] = proc(event: E) {.gcsafe, raises:[].}
 
 proc subscribe*[E: Event](contract: Contract,
                           _: type E,
@@ -16,13 +16,9 @@ proc subscribe*[E: Event](contract: Contract,
   let topic = topic($E, E.fieldTypes).toArray
   let filter = EventFilter(address: contract.address, topics: @[topic])
 
-  proc logHandler(logResult: ?!Log) {.raises: [].} =
-    without log =? logResult, error:
-      handler(failure(E, error))
-      return
-
+  proc logHandler(log: Log) {.raises: [].} =
     if event =? E.decode(log.data, log.topics):
-      handler(success(event))
+      handler(event)
 
   contract.provider.subscribe(filter, logHandler)
 
diff --git a/ethers/provider.nim b/ethers/provider.nim
index 8b2b1c1..d3db60f 100644
--- a/ethers/provider.nim
+++ b/ethers/provider.nim
@@ -57,8 +57,8 @@ type
     effectiveGasPrice*: ?UInt256
     status*: TransactionStatus
     transactionType* {.serialize("type"), deserialize("type").}: TransactionType
-  LogHandler* = proc(log: ?!Log) {.gcsafe, raises:[].}
-  BlockHandler* = proc(blck: ?!Block) {.gcsafe, raises:[].}
+  LogHandler* = proc(log: Log) {.gcsafe, raises:[].}
+  BlockHandler* = proc(blck: Block) {.gcsafe, raises:[].}
   Topic* = array[32, byte]
   Block* {.serialize.} = object
     number*: ?BlockNumber
@@ -239,8 +239,8 @@ proc confirm*(
   let blockEvent = newAsyncEvent()
   blockEvent.fire()
 
-  proc onBlock(blckResult: ?!Block) =
-    if blck =? blckResult and number =? blck.number:
+  proc onBlock(blck: Block) =
+    if number =? blck.number:
       blockNumber = number
       blockEvent.fire()
 
diff --git a/ethers/subscriptions.nim b/ethers/subscriptions.nim
index b71001e..eb661b3 100644
--- a/ethers/subscriptions.nim
+++ b/ethers/subscriptions.nim
@@ -92,11 +92,11 @@ proc processBlock(
       return false
     let logs = await subscriptions.getLogs(blck)
     for handler in subscriptions.blockSubscriptions.values:
-      handler(success blck)
+      handler(blck)
     for (id, logs) in logs.pairs:
       if (_, handler) =? subscriptions.logSubscriptions.?[id]:
         for log in logs:
-          handler(success log)
+          handler(log)
     return true
   except ProviderError:
     return false
diff --git a/testmodule/providers/jsonrpc/testJsonRpcProvider.nim b/testmodule/providers/jsonrpc/testJsonRpcProvider.nim
index fae1e07..133060f 100644
--- a/testmodule/providers/jsonrpc/testJsonRpcProvider.nim
+++ b/testmodule/providers/jsonrpc/testJsonRpcProvider.nim
@@ -49,7 +49,7 @@ for url in ["ws://" & providerUrl, "http://"  & providerUrl]:
       let oldBlock = !await provider.getBlock(BlockTag.latest)
       discard await provider.send("evm_mine")
       var newBlock: Block
-      let blockHandler = proc(blck: ?!Block) {.raises:[].}= newBlock = blck.value
+      let blockHandler = proc(blck: Block) = newBlock = blck
       let subscription = await provider.subscribe(blockHandler)
       discard await provider.send("evm_mine")
       check eventually newBlock.number.isSome
diff --git a/testmodule/providers/jsonrpc/testJsonRpcSubscriptions.nim b/testmodule/providers/jsonrpc/testJsonRpcSubscriptions.nim
index 4a885f3..f26c647 100644
--- a/testmodule/providers/jsonrpc/testJsonRpcSubscriptions.nim
+++ b/testmodule/providers/jsonrpc/testJsonRpcSubscriptions.nim
@@ -1,6 +1,5 @@
 import std/os
 import pkg/asynctest/chronos/unittest
-import pkg/serde
 import pkg/json_rpc/rpcclient
 import pkg/json_rpc/rpcserver
 import ethers/providers/jsonrpc
@@ -20,8 +19,8 @@ for url in ["ws://" & providerUrl, "http://"  & providerUrl]:
 
     test "subscribes to new blocks":
       var latestBlock: Block
-      proc callback(blck: ?!Block) =
-        latestBlock = blck.value
+      proc callback(blck: Block) =
+        latestBlock = blck
       let subscription = await provider.subscribe(callback)
       discard await provider.send("evm_mine")
       check eventually latestBlock.number.isSome
@@ -31,9 +30,8 @@ for url in ["ws://" & providerUrl, "http://"  & providerUrl]:
 
     test "stops listening to new blocks when unsubscribed":
       var count = 0
-      proc callback(blck: ?!Block) =
-        if blck.isOk:
-          inc count
+      proc callback(blck: Block) =
+        inc count
       let subscription = await provider.subscribe(callback)
       discard await provider.send("evm_mine")
       check eventually count > 0
@@ -44,16 +42,15 @@ for url in ["ws://" & providerUrl, "http://"  & providerUrl]:
       check count == 0
 
     test "duplicate unsubscribe is harmless":
-      proc callback(blck: ?!Block) = discard
+      proc callback(blck: Block) = discard
       let subscription = await provider.subscribe(callback)
       await subscription.unsubscribe()
       await subscription.unsubscribe()
 
     test "stops listening to new blocks when provider is closed":
       var count = 0
-      proc callback(blck: ?!Block) =
-        if blck.isOk:
-          inc count
+      proc callback(blck: Block) =
+        inc count
       discard await provider.subscribe(callback)
       discard await provider.send("evm_mine")
       check eventually count > 0
diff --git a/testmodule/testContracts.nim b/testmodule/testContracts.nim
index 487b186..bca0146 100644
--- a/testmodule/testContracts.nim
+++ b/testmodule/testContracts.nim
@@ -157,10 +157,7 @@ for url in ["ws://"  & providerUrl, "http://"  & providerUrl]:
     test "receives events when subscribed":
       var transfers: seq[Transfer]
 
-      proc handleTransfer(transferRes: ?!Transfer) =
-        without transfer =? transferRes, error:
-          echo error.msg
-
+      proc handleTransfer(transfer: Transfer) =
         transfers.add(transfer)
 
       let signer0 = provider.getSigner(accounts[0])
@@ -182,9 +179,8 @@ for url in ["ws://"  & providerUrl, "http://"  & providerUrl]:
     test "stops receiving events when unsubscribed":
       var transfers: seq[Transfer]
 
-      proc handleTransfer(transferRes: ?!Transfer) =
-        if transfer =? transferRes:
-          transfers.add(transfer)
+      proc handleTransfer(transfer: Transfer) =
+        transfers.add(transfer)
 
       let signer0 = provider.getSigner(accounts[0])