diff --git a/vm/src/builtins/bytearray.rs b/vm/src/builtins/bytearray.rs
index c811c3efad..d0b6a8c0c5 100644
--- a/vm/src/builtins/bytearray.rs
+++ b/vm/src/builtins/bytearray.rs
@@ -545,11 +545,11 @@ impl PyByteArray {
     }
 
     #[pymethod(name = "splitlines")]
-    fn splitlines(&self, options: anystr::SplitLinesArgs, vm: &VirtualMachine) -> PyResult {
+    fn splitlines(&self, options: anystr::SplitLinesArgs, vm: &VirtualMachine) -> PyObjectRef {
         let lines = self
             .borrow_value()
             .splitlines(options, |x| vm.ctx.new_bytearray(x.to_vec()));
-        Ok(vm.ctx.new_list(lines))
+        vm.ctx.new_list(lines)
     }
 
     #[pymethod(name = "zfill")]
@@ -607,9 +607,8 @@ impl PyByteArray {
     }
 
     #[pymethod(name = "reverse")]
-    fn reverse(&self) -> PyResult<()> {
+    fn reverse(&self) {
         self.borrow_value_mut().elements.reverse();
-        Ok(())
     }
 
     #[pymethod]
diff --git a/vm/src/builtins/bytes.rs b/vm/src/builtins/bytes.rs
index d0ea302674..6fb88de3ec 100644
--- a/vm/src/builtins/bytes.rs
+++ b/vm/src/builtins/bytes.rs
@@ -118,8 +118,8 @@ impl PyBytes {
     }
 
     #[pymethod(name = "__sizeof__")]
-    fn sizeof(&self) -> PyResult<usize> {
-        Ok(size_of::<Self>() + self.inner.elements.len() * size_of::<u8>())
+    fn sizeof(&self) -> usize {
+        size_of::<Self>() + self.inner.elements.len() * size_of::<u8>()
     }
 
     #[pymethod(name = "__add__")]
@@ -387,11 +387,11 @@ impl PyBytes {
     }
 
     #[pymethod(name = "splitlines")]
-    fn splitlines(&self, options: anystr::SplitLinesArgs, vm: &VirtualMachine) -> PyResult {
+    fn splitlines(&self, options: anystr::SplitLinesArgs, vm: &VirtualMachine) -> PyObjectRef {
         let lines = self
             .inner
             .splitlines(options, |x| vm.ctx.new_bytes(x.to_vec()));
-        Ok(vm.ctx.new_list(lines))
+        vm.ctx.new_list(lines)
     }
 
     #[pymethod(name = "zfill")]
diff --git a/vm/src/builtins/int.rs b/vm/src/builtins/int.rs
index 064498674f..4af72d556f 100644
--- a/vm/src/builtins/int.rs
+++ b/vm/src/builtins/int.rs
@@ -570,11 +570,8 @@ impl PyInt {
     }
 
     #[pymethod(name = "as_integer_ratio")]
-    fn as_integer_ratio(&self, vm: &VirtualMachine) -> PyResult {
-        Ok(vm.ctx.new_tuple(vec![
-            vm.ctx.new_bigint(&self.value),
-            vm.ctx.new_bigint(&BigInt::one()),
-        ]))
+    fn as_integer_ratio(&self, vm: &VirtualMachine) -> (PyObjectRef, BigInt) {
+        (vm.ctx.new_bigint(&self.value), BigInt::one())
     }
 
     #[pymethod]
diff --git a/vm/src/builtins/list.rs b/vm/src/builtins/list.rs
index c77228de53..c2314e5e28 100644
--- a/vm/src/builtins/list.rs
+++ b/vm/src/builtins/list.rs
@@ -117,13 +117,13 @@ impl PyList {
     }
 
     #[pymethod(name = "__iadd__")]
-    fn iadd(zelf: PyRef<Self>, other: PyObjectRef, vm: &VirtualMachine) -> PyResult {
+    fn iadd(zelf: PyRef<Self>, other: PyObjectRef, vm: &VirtualMachine) -> PyObjectRef {
         if let Ok(new_elements) = vm.extract_elements(&other) {
             let mut e = new_elements;
             zelf.borrow_value_mut().append(&mut e);
-            Ok(zelf.into_object())
+            zelf.into_object()
         } else {
-            Ok(vm.ctx.not_implemented())
+            vm.ctx.not_implemented()
         }
     }
 
diff --git a/vm/src/builtins/make_module.rs b/vm/src/builtins/make_module.rs
index 2af6882af9..b3b40ce421 100644
--- a/vm/src/builtins/make_module.rs
+++ b/vm/src/builtins/make_module.rs
@@ -320,8 +320,8 @@ mod decl {
     }
 
     #[pyfunction]
-    fn globals(vm: &VirtualMachine) -> PyResult<PyDictRef> {
-        Ok(vm.current_globals().clone())
+    fn globals(vm: &VirtualMachine) -> PyDictRef {
+        vm.current_globals().clone()
     }
 
     #[pyfunction]
diff --git a/vm/src/builtins/module.rs b/vm/src/builtins/module.rs
index 76ae4e3a3f..06aee7dacb 100644
--- a/vm/src/builtins/module.rs
+++ b/vm/src/builtins/module.rs
@@ -51,12 +51,7 @@ impl PyModule {
     }
 
     #[pymethod(magic)]
-    fn init(
-        zelf: PyRef<Self>,
-        name: PyStrRef,
-        doc: OptionalOption<PyStrRef>,
-        vm: &VirtualMachine,
-    ) -> PyResult<()> {
+    fn init(zelf: PyRef<Self>, name: PyStrRef, doc: OptionalOption<PyStrRef>, vm: &VirtualMachine) {
         debug_assert!(crate::pyobject::TypeProtocol::class(zelf.as_object())
             .slots
             .flags
@@ -67,7 +62,6 @@ impl PyModule {
             name.into_object(),
             doc.flatten().into_pyobject(vm),
         );
-        Ok(())
     }
 
     fn name(zelf: PyRef<Self>, vm: &VirtualMachine) -> Option<String> {
diff --git a/vm/src/builtins/object.rs b/vm/src/builtins/object.rs
index 51f410b809..c4e9a5e65d 100644
--- a/vm/src/builtins/object.rs
+++ b/vm/src/builtins/object.rs
@@ -172,8 +172,8 @@ impl PyBaseObject {
     }
 
     #[pyclassmethod(magic)]
-    fn subclasshook(_args: FuncArgs, vm: &VirtualMachine) -> PyResult {
-        Ok(vm.ctx.not_implemented())
+    fn subclasshook(_args: FuncArgs, vm: &VirtualMachine) -> PyObjectRef {
+        vm.ctx.not_implemented()
     }
 
     #[pyclassmethod(magic)]
diff --git a/vm/src/builtins/pystr.rs b/vm/src/builtins/pystr.rs
index 58e90a9ed3..650a679939 100644
--- a/vm/src/builtins/pystr.rs
+++ b/vm/src/builtins/pystr.rs
@@ -572,8 +572,8 @@ impl PyStr {
     }
 
     #[pymethod(name = "__rmod__")]
-    fn rmod(&self, _values: PyObjectRef, vm: &VirtualMachine) -> PyResult {
-        Ok(vm.ctx.not_implemented())
+    fn rmod(&self, _values: PyObjectRef, vm: &VirtualMachine) -> PyObjectRef {
+        vm.ctx.not_implemented()
     }
 
     #[pymethod]
diff --git a/vm/src/stdlib/zlib.rs b/vm/src/stdlib/zlib.rs
index 36a7aeb90c..166c306c68 100644
--- a/vm/src/stdlib/zlib.rs
+++ b/vm/src/stdlib/zlib.rs
@@ -41,32 +41,24 @@ mod decl {
 
     /// Compute an Adler-32 checksum of data.
     #[pyfunction]
-    fn adler32(data: PyBytesRef, begin_state: OptionalArg<i32>, vm: &VirtualMachine) -> PyResult {
+    fn adler32(data: PyBytesRef, begin_state: OptionalArg<i32>) -> u32 {
         let data = data.borrow_value();
-
         let begin_state = begin_state.unwrap_or(1);
 
         let mut hasher = Adler32::from_value(begin_state as u32);
         hasher.update_buffer(data);
-
-        let checksum: u32 = hasher.hash();
-
-        Ok(vm.ctx.new_int(checksum))
+        hasher.hash()
     }
 
     /// Compute a CRC-32 checksum of data.
     #[pyfunction]
-    fn crc32(data: PyBytesRef, begin_state: OptionalArg<i32>, vm: &VirtualMachine) -> PyResult {
+    fn crc32(data: PyBytesRef, begin_state: OptionalArg<i32>) -> u32 {
         let data = data.borrow_value();
-
         let begin_state = begin_state.unwrap_or(0);
 
         let mut hasher = Crc32::new_with_initial(begin_state as u32);
         hasher.update(data);
-
-        let checksum: u32 = hasher.finalize();
-
-        Ok(vm.ctx.new_int(checksum))
+        hasher.finalize()
     }
 
     /// Returns a bytes object containing compressed data.