diff --git a/core/src/types/operator/builder.rs b/core/src/types/operator/builder.rs
index 21b98be9e87..012a903f81f 100644
--- a/core/src/types/operator/builder.rs
+++ b/core/src/types/operator/builder.rs
@@ -102,9 +102,13 @@ impl Operator {
     /// TODO: improve those examples
     /// # Examples
     /// ```
-    /// let op = Operator::from_uri("fs://?root=/tmp/test", vec![])?
+    /// # use anyhow::Result;
+    /// use opendal::Operator;
     ///
-    /// Ok(())
+    /// fn test() -> Result<()> {
+    ///     let op = Operator::from_uri("fs://?root=/tmp/test", vec![])?;
+    ///     Ok(())
+    /// }
     /// ```
     pub fn from_uri(
         uri: &str,
diff --git a/core/src/types/operator/registry.rs b/core/src/types/operator/registry.rs
index a1adb6beb53..aa57bdc59fe 100644
--- a/core/src/types/operator/registry.rs
+++ b/core/src/types/operator/registry.rs
@@ -1,3 +1,20 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
 use std::cell::LazyCell;
 use std::collections::HashMap;