diff --git a/readme.md b/readme.md
index 0309f96..8820d54 100644
--- a/readme.md
+++ b/readme.md
@@ -224,7 +224,7 @@ class MyModelQuery extends ActiveQuery
                 $bitFlagsConditions[] = "$bitFlag & $mask = $res";
             }
         }
-        return new Expression(implode('and', $bitFlagsConditions));
+        return new Expression(implode(' and ', $bitFlagsConditions));
     }
 }
 ```