class_docstr: Importer mock using PEP 451 APIs.
code: def find_spec(self, fullname, path=None, parent=None):
      try:
          module = self.modules[fullname]
      except KeyError:
          return None
      spec = util.spec_from_file_location(
          fullname,
          module.__file__,
          loader=self,
          submodule_search_locations=getattr(module, "__path__", None),
      )
      return spec
  
imports: import builtins
  import contextlib
  import errno
  import functools
  from importlib import machinery, util, invalidate_caches
  import marshal
  import os
  import os.path
  from test.support import import_helper
  from test.support import os_helper
  import unittest
  import sys
  import tempfile
  import types
label_desc: Use image node_id 1 for calling the mock_spec obj's underlying member method code with example usage: obj.find_spec(fullname, path, parent) and returns: spec, None