From 127108165eaee5aced9023b826b17ef855a1085b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mamy=20Andr=C3=A9-Ratsimbazafy?= <mamy_github@numforge.co>
Date: Thu, 21 Jan 2021 14:43:49 +0100
Subject: [PATCH] address
 https://github.com/status-im/nimbus-eth2/pull/2250#discussion_r561819858

---
 beacon_chain/spec/signatures_batch.nim | 36 +++++++++++++-------------
 1 file changed, 18 insertions(+), 18 deletions(-)

diff --git a/beacon_chain/spec/signatures_batch.nim b/beacon_chain/spec/signatures_batch.nim
index 9aeb852c33..a3f245f9fb 100644
--- a/beacon_chain/spec/signatures_batch.nim
+++ b/beacon_chain/spec/signatures_batch.nim
@@ -35,26 +35,26 @@ func addSignatureSet[T](
   ## Add a new signature set triplet (pubkey, message, signature)
   ## to a collection of signature sets for batch verification.
   ## Can return false if `signature` wasn't deserialized to a valid BLS signature.
-  try:
-    let signing_root = compute_signing_root(
-        sszObj,
-        get_domain(
-          state.fork, domain,
-          epoch,
-          state.genesis_validators_root
-        )
-      ).data
-
-    sigs.add((
-      pubkey,
-      signing_root,
-      signature.blsValue
-    ))
-
-    return true
-  except FieldError: # bad discriminant when accessing signature.blsValue
+  if signature.kind != Real:
     return false
 
+  let signing_root = compute_signing_root(
+      sszObj,
+      get_domain(
+        state.fork, domain,
+        epoch,
+        state.genesis_validators_root
+      )
+    ).data
+
+  sigs.add((
+    pubkey,
+    signing_root,
+    signature.blsValue
+  ))
+
+  return true
+
 proc aggregateAttesters(
       attestation: IndexedAttestation,
       state: BeaconState