class_docstr: check that 'import monai.xx.file_name' returns a module
code: def test_files(self):
      src_dir = os.path.dirname(os.path.dirname(__file__))
      monai_dir = os.path.join(src_dir, "monai")
      py_files = glob.glob(
          os.path.join(monai_dir, "**", "*.py"), recursive=True
      )
      for x in py_files:
          if os.path.basename(x).startswith("_"):
              continue
          mod_name = x[len(src_dir) : -3]  # create relative path
          mod_name = mod_name[1:].replace(mod_name[0], ".")
          mod, cls = mod_name.rsplit(".", 1)
          obj, exist = optional_import(mod, name=cls)
          if exist:
              self.assertTrue(inspect.ismodule(obj), msg=mod_name)
  
file_path: MONAI/tests/test_alias.py
imports: from __future__ import annotations
  import glob
  import inspect
  import os
  import unittest
  from monai.utils import optional_import
label_desc: Use image node_id 1 for calling the TestModuleAlias obj's underlying member method code with example usage: obj.test_files() without return types