diff --git a/bindings/python/ggwave.pyx b/bindings/python/ggwave.pyx
index a9df2ff..07fc2e8 100644
--- a/bindings/python/ggwave.pyx
+++ b/bindings/python/ggwave.pyx
@@ -1,3 +1,4 @@
+# cython: language_level=3str
 cimport cython
 
 from libc.stdio cimport stderr