diff --git a/python/argmin-testfunctions-py/Cargo.toml b/python/argmin-testfunctions-py/Cargo.toml
index e7619d5ab..28bee0d83 100644
--- a/python/argmin-testfunctions-py/Cargo.toml
+++ b/python/argmin-testfunctions-py/Cargo.toml
@@ -20,4 +20,4 @@ crate-type = ["cdylib"]
 [dependencies]
 argmin_testfunctions = { version = "0.2.0", path = "../../crates/argmin-testfunctions" }
 paste = "1"
-pyo3 = "=0.21.0"
+pyo3 = "0.23"
diff --git a/python/argmin-testfunctions-py/src/lib.rs b/python/argmin-testfunctions-py/src/lib.rs
index 5251f9214..de128e39d 100644
--- a/python/argmin-testfunctions-py/src/lib.rs
+++ b/python/argmin-testfunctions-py/src/lib.rs
@@ -100,7 +100,7 @@ func!(styblinski_tang);
 func!(threehumpcamel, num = 2);
 
 #[pymodule]
-fn argmin_testfunctions_py(_py: Python, m: &PyModule) -> PyResult<()> {
+fn argmin_testfunctions_py(_py: Python, m: &Bound<'_, PyModule>) -> PyResult<()> {
     add_function!(m, ackley);
     add_function!(m, beale);
     add_function!(m, booth);