diff --git a/libs/langchain/tests/unit_tests/schema/runnable/test_utils.py b/libs/langchain/tests/unit_tests/schema/runnable/test_utils.py
index aeec3a7339..9f6d39f619 100644
--- a/libs/langchain/tests/unit_tests/schema/runnable/test_utils.py
+++ b/libs/langchain/tests/unit_tests/schema/runnable/test_utils.py
@@ -1,3 +1,5 @@
+from typing import Callable
+
 import pytest
 
 from langchain.schema.runnable.utils import (
@@ -6,7 +8,6 @@ from langchain.schema.runnable.utils import (
 )
 
 
-# Test get_lambda_source function
 @pytest.mark.parametrize(
     "func, expected_source",
     [
@@ -15,7 +16,8 @@ from langchain.schema.runnable.utils import (
         (lambda x: x if x > 0 else 0, "lambda x: x if x > 0 else 0"),
     ],
 )
-def test_get_lambda_source(func, expected_source):
+def test_get_lambda_source(func: Callable, expected_source: str) -> None:
+    """Test get_lambda_source function"""
     source = get_lambda_source(func)
     assert source == expected_source
 
@@ -27,6 +29,7 @@ def test_get_lambda_source(func, expected_source):
         ("line 1\nline 2\nline 3", "ax", "line 1\n  line 2\n  line 3"),
     ],
 )
-def test_indent_lines_after_first(text, prefix, expected_output):
+def test_indent_lines_after_first(text: str, prefix: str, expected_output: str) -> None:
+    """Test indent_lines_after_first function"""
     indented_text = indent_lines_after_first(text, prefix)
     assert indented_text == expected_output