diff --git a/src/ops/py_factory.rs b/src/ops/py_factory.rs
index 6ed35adf..fc2794e0 100644
--- a/src/ops/py_factory.rs
+++ b/src/ops/py_factory.rs
@@ -6,7 +6,7 @@ use futures::FutureExt;
 use pyo3::{
     exceptions::PyException,
     pyclass, pymethods,
-    types::{IntoPyDict, PyAnyMethods, PyString, PyTuple},
+    types::{IntoPyDict, PyAnyMethods, PyList, PyString, PyTuple},
     Bound, IntoPyObjectExt, Py, PyAny, PyResult, Python,
 };
 use pythonize::pythonize;
@@ -22,6 +22,70 @@ use super::sdk::{
     ExecutorFuture, FlowInstanceContext, SimpleFunctionExecutor, SimpleFunctionFactory,
 };
 
+fn basic_value_to_py_object<'py>(
+    py: Python<'py>,
+    v: &value::BasicValue,
+) -> PyResult<Bound<'py, PyAny>> {
+    let result = match v {
+        value::BasicValue::Bytes(v) => v.into_bound_py_any(py)?,
+        value::BasicValue::Str(v) => v.into_bound_py_any(py)?,
+        value::BasicValue::Bool(v) => v.into_bound_py_any(py)?,
+        value::BasicValue::Int64(v) => v.into_bound_py_any(py)?,
+        value::BasicValue::Float32(v) => v.into_bound_py_any(py)?,
+        value::BasicValue::Float64(v) => v.into_bound_py_any(py)?,
+        value::BasicValue::Vector(v) => v
+            .iter()
+            .map(|v| basic_value_to_py_object(py, v))
+            .collect::<PyResult<Vec<_>>>()?
+            .into_bound_py_any(py)?,
+        _ => {
+            return Err(PyException::new_err(format!(
+                "unsupported value type: {}",
+                v.kind()
+            )))
+        }
+    };
+    Ok(result)
+}
+
+fn field_values_to_py_object<'py, 'a>(
+    py: Python<'py>,
+    values: impl Iterator<Item = &'a value::Value>,
+) -> PyResult<Bound<'py, PyAny>> {
+    let fields = values
+        .map(|v| value_to_py_object(py, v))
+        .collect::<PyResult<Vec<_>>>()?;
+    Ok(PyTuple::new(py, fields)?.into_any())
+}
+
+fn value_to_py_object<'py>(py: Python<'py>, v: &value::Value) -> PyResult<Bound<'py, PyAny>> {
+    let result = match v {
+        value::Value::Null => py.None().into_bound(py),
+        value::Value::Basic(v) => basic_value_to_py_object(py, v)?,
+        value::Value::Struct(v) => field_values_to_py_object(py, v.fields.iter())?,
+        value::Value::Collection(v) | value::Value::List(v) => {
+            let rows = v
+                .iter()
+                .map(|v| field_values_to_py_object(py, v.0.fields.iter()))
+                .collect::<PyResult<Vec<_>>>()?;
+            PyList::new(py, rows)?.into_any()
+        }
+        value::Value::Table(v) => {
+            let rows = v
+                .iter()
+                .map(|(k, v)| {
+                    field_values_to_py_object(
+                        py,
+                        std::iter::once(&value::Value::from(k.clone())).chain(v.0.fields.iter()),
+                    )
+                })
+                .collect::<PyResult<Vec<_>>>()?;
+            PyList::new(py, rows)?.into_any()
+        }
+    };
+    Ok(result)
+}
+
 fn basic_value_from_py_object<'py>(
     typ: &schema::BasicValueType,
     v: &Bound<'py, PyAny>,
@@ -159,7 +223,7 @@ impl SimpleFunctionExecutor for Arc<PyFunctionExecutor> {
             Python::with_gil(|py| -> Result<_> {
                 let mut args = Vec::with_capacity(self.num_positional_args);
                 for v in input[0..self.num_positional_args].iter() {
-                    args.push(pythonize(py, v)?);
+                    args.push(value_to_py_object(py, v)?);
                 }
 
                 let kwargs = if self.kw_args_names.is_empty() {
@@ -171,7 +235,7 @@ impl SimpleFunctionExecutor for Arc<PyFunctionExecutor> {
                         .iter()
                         .zip(input[self.num_positional_args..].iter())
                     {
-                        kwargs.push((name.bind(py), pythonize(py, v)?));
+                        kwargs.push((name.bind(py), value_to_py_object(py, v)?));
                     }
                     Some(kwargs)
                 };