diff --git a/setup.py b/setup.py
index 4b9569b..2832ca1 100644
--- a/setup.py
+++ b/setup.py
@@ -3,7 +3,7 @@
 setup(
     ext_modules=[
         Extension(
-            name="testpackage.mydemo",  # as it would be imported
+            name="testpackage._mydemo",  # as it would be imported
                             # may include packages/namespaces separated by `.`
 
             sources=["./src/testpackage/c/mydemo.c"], # all sources are compiled into a single binary file
diff --git a/src/testpackage/c/mydemo.c b/src/testpackage/c/mydemo.c
index 284ec82..8193900 100644
--- a/src/testpackage/c/mydemo.c
+++ b/src/testpackage/c/mydemo.c
@@ -22,15 +22,15 @@ static PyMethodDef mydemoMethods[] = {
 
 static struct PyModuleDef spammodule = {
     PyModuleDef_HEAD_INIT,
-    "mydemo",   /* name of module */
-    "this is some mydemo's doc", /* module documentation, may be NULL */
+    "_mydemo",   /* name of module */
+    "this is a mydemo's doc", /* module documentation, may be NULL */
     -1,       /* size of per-interpreter state of the module,
                  or -1 if the module keeps state in global variables. */
     mydemoMethods
 };
 
 PyMODINIT_FUNC
-PyInit_mydemo(void)
+PyInit__mydemo(void) /* module name is _mydemo */
 {
     PyObject *m;
 
diff --git a/src/testpackage/main.py b/src/testpackage/main.py
new file mode 100644
index 0000000..be1ef74
--- /dev/null
+++ b/src/testpackage/main.py
@@ -0,0 +1,16 @@
+"""module run.py docstring"""
+
+from . import _mydemo
+
+def hello():
+    """test message""" 
+    print('Hello world, this is "run.py"')
+
+def mydemo():
+    print("_mydemo.print_hello()")
+    output  = _mydemo.print_hello()
+    print("output:", output)
+    print(f"__doc__ = {_mydemo.__doc__}")
+    print(f"__file__ = {_mydemo.__file__}")
+    print(f"__name__ = {_mydemo.__name__}")
+    print(f"__package__ = {_mydemo.__package__}")
diff --git a/src/testpackage/run.py b/src/testpackage/run.py
deleted file mode 100644
index 6abd760..0000000
--- a/src/testpackage/run.py
+++ /dev/null
@@ -1,15 +0,0 @@
-"""module run.py docstring"""
-
-import math
-from . import mydemo
-
-def cos10():
-    """cos(10)""" 
-    return math.cos(10)
-
-def hello():
-    """test message""" 
-    print('Hello world, this is "run.py"')
-
-output  = mydemo.print_hello()
-print(output)
diff --git a/src/testpackage/test/test.py b/src/testpackage/test/test.py
index 00f8df5..963350c 100644
--- a/src/testpackage/test/test.py
+++ b/src/testpackage/test/test.py
@@ -1,10 +1,6 @@
 """test package"""
 
-from testpackage import run
-from testpackage import mydemo
+from testpackage import main
 
-print(run.cos10())
-run.hello()
-
-value = mydemo.print_hello()
-print(f"output from mydemo.print_hello(): {value}")
+main.hello()
+main.mydemo()