class_docstr: Unit test for operator loader.
class_docstr_tok: ["Unit","test","for","operator","loader","."]
code: def test_invalid_old(self):
      op = ops.local.old_format_op_invalid(10)
      with self.assertRaises(RuntimeError) as e:
          op(10)
          self.assertEqual(
              e.msg,
              "Loading operator with error:No module named 'NotExistPackage'",
          )
  
file_path: towhee/tests/unittests/runtime/test_operator_loader.py
imports: import unittest
  from ..None import operator_cache
  from towhee.runtime import ops
  from towhee.runtime.operator_manager.operator_loader import OperatorLoader
label_desc: Use image node_id 3 for calling the TestOperatorLoader obj's underlying member method code with example usage: obj.test_invalid_old() without return types