code: def test_no_input(self):
      with self.assertRaisesRegexp(ImportError, ""):
          require_module([], mandatory=True)
      with self.assertRaisesRegexp(ImportError, ""):
          require_module(None, mandatory=True)
  
file_path: NiftyNet/tests/util_import_test.py
imports: import tensorflow
  from niftynet.utilities.util_import import require_module
  from tests.niftynet_testcase import NiftyNetTestCase
label_desc: Use image node_id 7 for calling the OptionalPackageTest obj's underlying member method code with example usage: obj.test_no_input() without return types