diff --git a/modules/python/generator/visp_python_bindgen/generator_config.py b/modules/python/generator/visp_python_bindgen/generator_config.py
index e20351b93d..67b15576dc 100644
--- a/modules/python/generator/visp_python_bindgen/generator_config.py
+++ b/modules/python/generator/visp_python_bindgen/generator_config.py
@@ -80,7 +80,7 @@ def to_pcpp_args_list(self) -> List[str]:
 This only encompasses raw types
 '''
 IMMUTABLE_TYPES_REGEXS = [
-  '^(float|double|u?int\d+_t|unsigned|char|long|long\wlong|bool)$',
+  '^(float|double|u?int\d+_t|unsigned|unsigned int|size_t|ssize_t|char|long|long\wlong|bool)$',
   '^std::string$'
 ]