diff --git a/setup.py b/setup.py
index 6d0700a..49810e0 100644
--- a/setup.py
+++ b/setup.py
@@ -66,9 +66,11 @@ def parse_version_file(text: str) -> str:
 
 
 def find_python_packages() -> list[str]:
-    """Find all python packages (directories containing __init__.py files)."""
+    """
+    Find all python packages. (Directories containing __init__.py files.)
+    """
     root_path = Path(PACKAGE_NAME)
-    packages: set[str] = {PACKAGE_NAME}
+    packages: set[str] = set([PACKAGE_NAME])
 
     # Search recursively
     for init_file in root_path.rglob('__init__.py'):
@@ -76,7 +78,6 @@ def find_python_packages() -> list[str]:
 
     return sorted(packages)
 
-
 with open(PACKAGE_NAME + '/_version.py') as f:
     version = parse_version_file(f.read())