diff --git a/bigchaindb/common/transaction.py b/bigchaindb/common/transaction.py
index 24a3ae5d..7098d366 100644
--- a/bigchaindb/common/transaction.py
+++ b/bigchaindb/common/transaction.py
@@ -1236,7 +1236,9 @@ class Transaction(object):
     def resolve_class(operation):
         """For the given `tx` based on the `operation` key return its implementation class"""
 
-        if operation in list(Transaction.type_registry.keys()):
-            return Transaction.type_registry.get(operation)
-        else:
-            return Transaction.type_registry.get(Transaction.CREATE)
+        create_txn_class = Transaction.type_registry.get(Transaction.CREATE)
+        return Transaction.type_registry.get(operation, create_txn_class)
+
+    @classmethod
+    def validate_schema(cls, tx):
+        pass
diff --git a/bigchaindb/upsert_validator/validator_election.py b/bigchaindb/upsert_validator/validator_election.py
index d52cbdd9..e83d7264 100644
--- a/bigchaindb/upsert_validator/validator_election.py
+++ b/bigchaindb/upsert_validator/validator_election.py
@@ -131,3 +131,11 @@ class ValidatorElection(Transaction):
         _validate_schema(TX_SCHEMA_COMMON, tx)
         _validate_schema(TX_SCHEMA_CREATE, tx)
         _validate_schema(TX_SCHEMA_VALIDATOR_ELECTION, tx)
+
+    @classmethod
+    def create(cls, tx_signers, recipients, metadata=None, asset=None):
+        raise NotImplementedError
+
+    @classmethod
+    def transfer(cls, tx_signers, recipients, metadata=None, asset=None):
+        raise NotImplementedError