python file can't import module after change pybind target name

[argentea]

I move the test_basic.py to project root directory and change the import path.
Then, I change the target name in CMakeLists.txt and module name in test_basic.py.
Then, "mkdir build; cd build; cmake ...; make", and everything goes well.
However, when i run the test_basic.py, I get
"Traceback (most recent call last):
File "test_basic.py", line 2, in
import build.bind_example as m
ImportError: dynamic module does not define module export function (PyInit_bind_example)
".

Besides, when I change the target name back to cmake_example, the python file import module normally,

Attached files is the version which target name is changed.
CMakeLists.txt