feat: add sub package test

sub_package/__init__.py

@@ -0,0 +1,5 @@
+from .sub import sub_func
+
+__all__ = ["sub_func"]
+
+print("__sub_pacakge__.__init__")

sub_package/sub.py

@@ -0,0 +1,3 @@
+
+def sub_func():
+    print("call: sub_func")

sub_package_test.py

@@ -0,0 +1,6 @@
+#!/usr/bin/env python3
+
+import sub_package
+
+if __name__ == "__main__":
+    sub_package.sub_func()