diff --git a/contracts/BaseDocumentStore.sol b/contracts/BaseDocumentStore.sol
index b2308a8..a833267 100644
--- a/contracts/BaseDocumentStore.sol
+++ b/contracts/BaseDocumentStore.sol
@@ -48,6 +48,8 @@ contract BaseDocumentStore is Initializable {
   function _revoke(bytes32 document) internal onlyNotRevoked(document) returns (bool) {
     documentRevoked[document] = block.number;
     emit DocumentRevoked(document);
+
+    return true;
   }
 
   function _bulkRevoke(bytes32[] memory documents) internal {
diff --git a/contracts/DocumentStoreWithRevokeReasons.sol b/contracts/DocumentStoreWithRevokeReasons.sol
index 7546831..483a914 100644
--- a/contracts/DocumentStoreWithRevokeReasons.sol
+++ b/contracts/DocumentStoreWithRevokeReasons.sol
@@ -21,6 +21,8 @@ contract DocumentStoreWithRevokeReasons is DocumentStore {
     revoke(document);
     revokeReason[document] = reason;
     emit DocumentRevokedWithReason(document, reason);
+
+    return true;
   }
 
   function bulkRevoke(bytes32[] memory documents, uint256 reason) public {