diff --git a/src/main/java/net/hostsharing/hsadminng/rbac/rbacdef/InsertTriggerGenerator.java b/src/main/java/net/hostsharing/hsadminng/rbac/rbacdef/InsertTriggerGenerator.java
index 7afd1941..5303c27e 100644
--- a/src/main/java/net/hostsharing/hsadminng/rbac/rbacdef/InsertTriggerGenerator.java
+++ b/src/main/java/net/hostsharing/hsadminng/rbac/rbacdef/InsertTriggerGenerator.java
@@ -1,6 +1,7 @@
 package net.hostsharing.hsadminng.rbac.rbacdef;
 
 import java.util.Optional;
+import java.util.function.BinaryOperator;
 import java.util.stream.Stream;
 
 import static net.hostsharing.hsadminng.rbac.rbacdef.RbacView.Permission.INSERT;
@@ -142,19 +143,20 @@ public class InsertTriggerGenerator {
 
     private Optional<RbacView.RbacGrantDefinition> getOptionalInsertGrant() {
         return getInsertGrants()
-                .reduce((x, y) -> {
-                    throw new IllegalStateException("only a single INSERT permission grant allowed");
-                });
+                .reduce(singleton());
     }
 
     private Optional<RbacView.RbacRoleDefinition> getOptionalInsertSuperRole() {
         return getInsertGrants()
                 .map(RbacView.RbacGrantDefinition::getSuperRoleDef)
-                .reduce((x, y) -> {
-                    throw new IllegalStateException("only a single INSERT permission grant allowed");
-                });
+                .reduce(singleton());
     }
 
+    private static <T> BinaryOperator<T> singleton() {
+        return (x, y) -> {
+            throw new IllegalStateException("only a single INSERT permission grant allowed");
+        };
+    }
 
     private static String toVar(final RbacView.RbacRoleDefinition roleDef) {
         return uncapitalize(roleDef.getEntityAlias().simpleName()) + capitalize(roleDef.getRole().roleName());