build breaks if the directory is too much nested

example/example3/__init__.py

+import logging
+import typing as tp
+
+logger = logging.getLogger(__name__)
+

example/example3/example3/__init__.py

+import logging
+import typing as tp
+
+logger = logging.getLogger(__name__)
+

example/example3/example3/example3/__init__.py

+import logging
+import typing as tp
+
+logger = logging.getLogger(__name__)
+

example/example3/example3/example3/test.pyx

+def test(a, b):
+    return a+b

example/setup.py

@@ -11,7 +11,8 @@ cython_multibuilds = [
     Multibuild('example_module', ['example_module\\test.pyx', 'example_module/test2.pyx',
                                   'example_module/test3/test3.pyx',
                                   'example_module/test_n.c']),
-    Extension('example2.example', ['example2/example.pyx'])
+    Extension('example2.example', ['example2/example.pyx']),
+    Multibuild('example3.example3.example3', ['example3/example3/example3/test.pyx'])
 ]
 
 # first argument is used directly by snakehouse, the rest and **kwargs are passed to

example/tests/test_test.py

@@ -2,10 +2,14 @@ from example_module.test import times_two
 from example_module.test2 import times_three, times_five
 from example_module.test3.test3 import times_four
 from example2.example import test
+from example3.example3.example3.test import test as test_three
 import unittest
 
 
 class TestExample(unittest.TestCase):
+    def test_three(self):
+        self.assertEqual(test_three(2, 3), 5)
+
     def test_test(self):
         self.assertEqual(test(2, 3), 5)