diff --git a/python/src/lib.rs b/python/src/lib.rs
index c904c23..4f3ed82 100644
--- a/python/src/lib.rs
+++ b/python/src/lib.rs
@@ -5,10 +5,7 @@ mod kdtree;
 mod rtree;
 pub(crate) mod util;
 
-use pyo3::exceptions::PyRuntimeWarning;
-use pyo3::intern;
 use pyo3::prelude::*;
-use pyo3::types::PyTuple;
 
 const VERSION: &str = env!("CARGO_PKG_VERSION");
 
@@ -19,15 +16,19 @@ fn ___version() -> &'static str {
 
 /// Raise RuntimeWarning for debug builds
 #[pyfunction]
-fn check_debug_build(py: Python) -> PyResult<()> {
+fn check_debug_build(_py: Python) -> PyResult<()> {
     #[cfg(debug_assertions)]
     {
-        let warnings_mod = py.import(intern!(py, "warnings"))?;
+        use pyo3::exceptions::PyRuntimeWarning;
+        use pyo3::intern;
+        use pyo3::types::PyTuple;
+
+        let warnings_mod = _py.import(intern!(_py, "warnings"))?;
         let warning = PyRuntimeWarning::new_err(
             "geoindex-rs has not been compiled in release mode. Performance will be degraded.",
         );
-        let args = PyTuple::new(py, vec![warning])?;
-        warnings_mod.call_method1(intern!(py, "warn"), args)?;
+        let args = PyTuple::new(_py, vec![warning])?;
+        warnings_mod.call_method1(intern!(_py, "warn"), args)?;
     }
 
     Ok(())