diff --git a/doc/python_api_reference_vDev.md b/doc/python_api_reference_vDev.md
index 68f37834e..8439360b6 100644
--- a/doc/python_api_reference_vDev.md
+++ b/doc/python_api_reference_vDev.md
@@ -4414,7 +4414,7 @@ def sample_write(
     obs_out_format: 'Literal["01", "b8", "r8", "ptb64", "hits", "dets"]' = '01',
     prepend_observables: bool = False,
     append_observables: bool = False,
-):
+) -> None:
     """Samples detection events from the circuit and writes them to a file.
 
     Args:
diff --git a/doc/stim.pyi b/doc/stim.pyi
index 9b305f107..d08243a74 100644
--- a/doc/stim.pyi
+++ b/doc/stim.pyi
@@ -3373,7 +3373,7 @@ class CompiledDetectorSampler:
         obs_out_format: 'Literal["01", "b8", "r8", "ptb64", "hits", "dets"]' = '01',
         prepend_observables: bool = False,
         append_observables: bool = False,
-    ):
+    ) -> None:
         """Samples detection events from the circuit and writes them to a file.
 
         Args:
diff --git a/glue/python/src/stim/__init__.pyi b/glue/python/src/stim/__init__.pyi
index 9b305f107..d08243a74 100644
--- a/glue/python/src/stim/__init__.pyi
+++ b/glue/python/src/stim/__init__.pyi
@@ -3373,7 +3373,7 @@ class CompiledDetectorSampler:
         obs_out_format: 'Literal["01", "b8", "r8", "ptb64", "hits", "dets"]' = '01',
         prepend_observables: bool = False,
         append_observables: bool = False,
-    ):
+    ) -> None:
         """Samples detection events from the circuit and writes them to a file.
 
         Args: