diff --git a/python/python/lance/fragment.py b/python/python/lance/fragment.py
index ce9334c682..49f0573007 100644
--- a/python/python/lance/fragment.py
+++ b/python/python/lance/fragment.py
@@ -366,9 +366,9 @@ def fragment_id(self):
     def count_rows(
         self, filter: Optional[Union[pa.compute.Expression, str]] = None
     ) -> int:
-        if filter is not None:
-            raise ValueError("Does not support filter at the moment")
-        return self._fragment.count_rows()
+        if isinstance(filter, pa.compute.Expression):
+            raise ValueError("Does not support pyarrow Expression at the moment")
+        return self._fragment.count_rows(filter)
 
     @property
     def num_deletions(self) -> int:
diff --git a/python/src/fragment.rs b/python/src/fragment.rs
index b5cb75fc3a..d29783921c 100644
--- a/python/src/fragment.rs
+++ b/python/src/fragment.rs
@@ -1,16 +1,5 @@
-// Copyright 2024 Lance Developers.
-//
-// Licensed 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.
+// SPDX-License-Identifier: Apache-2.0
+// SPDX-FileCopyrightText: Copyright The Lance Authors
 
 use std::fmt::Write as _;
 use std::sync::Arc;
@@ -127,11 +116,11 @@ impl FileFragment {
         PyLance(self.fragment.metadata().clone())
     }
 
-    #[pyo3(signature=(_filter=None))]
-    fn count_rows(&self, _filter: Option<String>) -> PyResult<usize> {
+    #[pyo3(signature=(filter=None))]
+    fn count_rows(&self, filter: Option<String>) -> PyResult<usize> {
         RT.runtime.block_on(async {
             self.fragment
-                .count_rows()
+                .count_rows(filter)
                 .await
                 .map_err(|e| PyIOError::new_err(e.to_string()))
         })